Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Nat Immunol ; 15(1): 63-71, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24270516

RESUMEN

Detailed understanding of the signaling intermediates that confer the sensing of intracellular viral nucleic acids for induction of type I interferons is critical for strategies to curtail viral mechanisms that impede innate immune defenses. Here we show that the activation of the microtubule-associated guanine nucleotide exchange factor GEF-H1, encoded by Arhgef2, is essential for sensing of foreign RNA by RIG-I-like receptors. Activation of GEF-H1 controls RIG-I-dependent and Mda5-dependent phosphorylation of IRF3 and induction of IFN-ß expression in macrophages. Generation of Arhgef2(-/-) mice revealed a pronounced signaling defect that prevented antiviral host responses to encephalomyocarditis virus and influenza A virus. Microtubule networks sequester GEF-H1 that upon activation is released to enable antiviral signaling by intracellular nucleic acid detection pathways.


Asunto(s)
Inmunidad Innata/inmunología , Microtúbulos/inmunología , ARN Viral/inmunología , Factores de Intercambio de Guanina Nucleótido Rho/inmunología , Transducción de Señal/inmunología , Animales , Células COS , Chlorocebus aethiops , Proteína 58 DEAD Box , ARN Helicasas DEAD-box/inmunología , ARN Helicasas DEAD-box/metabolismo , Expresión Génica/inmunología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Inmunidad Innata/genética , Immunoblotting , Virus de la Influenza A/genética , Factor 3 Regulador del Interferón/inmunología , Factor 3 Regulador del Interferón/metabolismo , Helicasa Inducida por Interferón IFIH1 , Interferón beta/genética , Interferón beta/inmunología , Interferón beta/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microscopía Confocal , Microtúbulos/metabolismo , Fosforilación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Intercambio de Guanina Nucleótido Rho/genética , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Transducción de Señal/genética
2.
Immunity ; 38(1): 153-65, 2013 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-23246312

RESUMEN

Circulatory antigens transit through the small intestine via the fenestrated capillaries in the lamina propria prior to entering into the draining lymphatics. But whether or how this process controls mucosal immune responses remains unknown. Here we demonstrate that dendritic cells (DCs) of the lamina propria can sample and process both circulatory and luminal antigens. Surprisingly, antigen cross-presentation by resident CX3CR1(+) DCs induced differentiation of precursor cells into CD8(+) T cells that expressed interleukin-10 (IL-10), IL-13, and IL-9 and could migrate into adjacent compartments. We conclude that lamina propria CX3CR1(+) DCs facilitate the surveillance of circulatory antigens and act as a conduit for the processing of self- and intestinally absorbed antigens, leading to the induction of CD8(+) T cells, that partake in the control of T cell activation during mucosal immune responses.


Asunto(s)
Presentación de Antígeno/inmunología , Linfocitos T CD8-positivos/inmunología , Células Dendríticas/inmunología , Mucosa Intestinal/inmunología , Activación de Linfocitos/inmunología , Animales , Antígenos/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/citología , Receptor 1 de Quimiocinas CX3C , Diferenciación Celular/inmunología , Reactividad Cruzada/inmunología , Células Dendríticas/metabolismo , Enteritis/inmunología , Enteritis/prevención & control , Epítopos de Linfocito T/inmunología , Mucosa Intestinal/citología , Intestino Delgado/inmunología , Ratones , Receptores de Quimiocina/inmunología , Receptores de Quimiocina/metabolismo
3.
Int J Mol Sci ; 21(4)2020 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-32075101

RESUMEN

Inflammasomes are intracellular multiple protein complexes that mount innate immune responses to tissue damage and invading pathogens. Their excessive activation is crucial in the development and pathogenesis of inflammatory disorders. Microtubules have been reported to provide the platform for mediating the assembly and activation of NLRP3 inflammasome. Recently, we have identified the microtubule-associated immune molecule guanine nucleotide exchange factor-H1 (GEF-H1) that is crucial in coupling microtubule dynamics to the initiation of microtubule-mediated immune responses. However, whether GEF-H1 also controls the activation of other immune receptors that require microtubules is still undefined. Here we employed GEF-H1-deficient mouse bone marrow-derived macrophages (BMDMs) to interrogate the impact of GEF-H1 on the activation of NLRP3 inflammasome. NLRP3 but not NLRC4 or AIM2 inflammasome-mediated IL-1ß production was dependent on dynamic microtubule network in wild-type (WT) BMDMs. However, GEF-H1 deficiency did not affect NLRP3-driven IL-1ß maturation and secretion in macrophages. Moreover, α-tubulin acetylation and mitochondria aggregations were comparable between WT and GEF-H1-deficient BMDMs in response to NLRP3 inducers. Further, GEF-H1 was not required for NLRP3-mediated immune defense against Salmonella typhimurium infection. Collectively, these findings suggest that the microtubule-associated immune modulator GEF-H1 is dispensable for microtubule-mediated NLRP3 activation and host defense in mouse macrophages.


Asunto(s)
Inflamasomas/metabolismo , Macrófagos/metabolismo , Microtúbulos/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Acetilación , Animales , Células de la Médula Ósea/citología , Células Cultivadas , Inmunidad Innata , Interleucina-1beta/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Nigericina/farmacología , Factores de Intercambio de Guanina Nucleótido Rho/deficiencia , Factores de Intercambio de Guanina Nucleótido Rho/genética , Infecciones por Salmonella/inmunología , Infecciones por Salmonella/patología , Salmonella typhimurium/patogenicidad
4.
Inflamm Bowel Dis ; 29(5): 783-797, 2023 05 02.
Artículo en Inglés | MEDLINE | ID: mdl-36617175

RESUMEN

BACKGROUND: Increased neutrophil extracellular trap (NET) formation and abundant NET-associated proteins are frequently found in the inflamed colon of patients with inflammatory bowel disease. Peptidyl arginine deiminase 4 (PAD4) activation is essential for the generation of NET and NET-mediated pathogenesis. However, the role of PAD4-dependent NET formation in murine inflammatory bowel disease models and the molecular mechanisms responsible for the altered gut barrier function are unknown. METHODS: Wild-type and Pad4 knockout (Pad4-/-) mice were administrated 3% dextran sulfate sodium (DSS) in their drinking water. Caco-2 monolayers were used to test the effect of NETs on intestinal barrier function and cytotoxicity. Histones were intrarectally administrated to wild-type mice to determine their effects on intestinal barrier function and cytotoxicity in vivo. RESULTS: PAD4 deficiency reduced the severity of DSS-induced colitis with decreased intestinal NET formation and enhanced gut barrier function and integrity in mice. NETs disrupted the barrier function in intestinal epithelial Caco-2 monolayers through their protein, rather than DNA, components. Pretreatment of NETs with histone inhibitors abrogated the effects on epithelial permeability. Consistent with these observations, adding purified histone proteins to Caco-2 monolayers significantly damaged epithelial barrier function, which was associated with the abnormal distribution and integrity of tight junctions as well as with increased cell death. Furthermore, intrarectal administration of histones damaged the intestinal barrier integrity and induced cytotoxicity in the mouse colon epithelium. CONCLUSIONS: PAD4-mediated NET formation has a detrimental role in acute colitis. NET-associated histones directly inhibit intestinal barrier function, resulting in cytotoxicity in vitro and in vivo.


Peptidyl arginine deiminase 4­dependent neutrophil extracellular trap formation is detrimental to intestinal barrier function in acute colitis. Neutrophil extracellular trap­associated histones altered the integrity of tight junction and adherens junction proteins as well as induced intestinal epithelial cell death that resulted in increased gut epithelium permeability.


Asunto(s)
Colitis , Trampas Extracelulares , Enfermedades Inflamatorias del Intestino , Humanos , Animales , Ratones , Trampas Extracelulares/metabolismo , Histonas/metabolismo , Células CACO-2 , Colitis/inducido químicamente , Enfermedades Inflamatorias del Intestino/patología , Permeabilidad , Mucosa Intestinal/patología , Modelos Animales de Enfermedad , Ratones Endogámicos C57BL
5.
Biomedicines ; 8(8)2020 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-32764411

RESUMEN

Aberrant neutrophil extracellular trap (NET) formation and the loss of barrier integrity in inflamed intestinal tissues have long been associated with inflammatory bowel disease (IBD). However, whether NETs alter intestinal epithelium permeability during colitis remains elusive. Here, we demonstrated that NETs promote the breakdown in intestinal barrier function for the pathogenesis of intestinal inflammation in mouse models of colitis. NETs were abundant in the colon of mice with colitis experimentally induced by dextran sulfate sodium (DSS) or 2,4,6-trinitrobenzene sulfonic acid (TNBS). Analysis of the intestinal barrier integrity revealed that NETs impaired gut permeability, enabling the initiation of luminal bacterial translocation and inflammation. Furthermore, NETs induced the apoptosis of epithelial cells and disrupted the integrity of tight junctions and adherens junctions. Intravenous administration of DNase I, an enzyme that dissolves the web-like DNA filaments of NETs, during colitis restored the mucosal barrier integrity which reduced the dissemination of luminal bacteria and attenuated intestinal inflammation in both DSS and TNBS models. We conclude that NETs serve a detrimental factor in the gut epithelial barrier function leading to the pathogenesis of mucosal inflammation during acute colitis.

6.
Front Immunol ; 9: 3086, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30671058

RESUMEN

The antiviral innate immunity is the first line of host defense against virus infections. In mammalian cells, viral infections initiate the expression of interferons (IFNs) in the host that in turn activate an antiviral defense program to restrict viral replications by induction of IFN stimulated genes (ISGs), which are largely regulated by the IFN-regulatory factor (IRF) family and signal transducer and activator of transcription (STAT) family transcription factors. The mechanisms of action of IRFs and STATs involve several post-translational modifications, complex formation, and nuclear translocation of these transcription factors. However, many viruses, including human immunodeficiency virus (HIV), Zika virus (ZIKV), and herpes simplex virus (HSV), have evolved strategies to evade host defense, including alteration in IRF and STAT post-translational modifications, disturbing the formation and nuclear translocation of the transcription complexes as well as proteolysis/degradation of IRFs and STATs. In this review, we discuss and summarize the molecular mechanisms by which how viral components may target IRFs and STATs to antagonize the establishment of antiviral host defense. The underlying host-viral interactions determine the outcome of viral infection. Gaining mechanistic insight into these processes will be crucial in understanding how viral replication can be more effectively controlled and in developing approaches to improve virus infection outcomes.


Asunto(s)
Factores Reguladores del Interferón/inmunología , Factores Reguladores del Interferón/metabolismo , Factores de Transcripción STAT/inmunología , Factores de Transcripción STAT/metabolismo , Proteínas Virales/metabolismo , Virosis/inmunología , Animales , Humanos , Inmunidad Innata , Interferón Tipo I/metabolismo , Quinasas Janus/metabolismo , Proteolisis , Transducción de Señal/inmunología , Receptores Toll-Like/metabolismo
7.
Virology ; 441(2): 146-51, 2013 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-23642353

RESUMEN

Dengue viruses (DENV), members of mosquito-borne Flaviviruses, are human pathogens of global significance. The virus enters the host cell through endocytosis and uncoating subsequent to a low pH-triggered conformational change of E protein in endosomes. The endosomes are active in antigen processing and the key enzyme involved is the gamma interferon-inducible lysosomal thiol reductase (GILT). Here, we sought to address the role of GILT in DENV2 entry using fibroblasts from wild type (WT) and GILT knockout (GILT(-/-)) mice (MFs) with defective antigen processing. Our results obtained using DENV2 infectious and Renilla luciferase reporter replicon RNAs show that WT MFs are relatively resistant and GILT(-/-) MFs are susceptible to DENV2 translation and replication. We show that DENV2 infection of WT MEFs induced autophagy based on an increased LC3-II/LC3-I ratio that is further enhanced in GILT(-/-) cells. The increased susceptibility of DENV2 infection in the GILT(-/-)MFs strongly correlates with increased autophagy.


Asunto(s)
Virus del Dengue/fisiología , Fibroblastos/virología , Interacciones Huésped-Patógeno , Oxidorreductasas/metabolismo , Internalización del Virus , Animales , Autofagia , Genes Reporteros , Luciferasas/análisis , Ratones , Ratones Noqueados , Oxidorreductasas/deficiencia , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro , Coloración y Etiquetado
8.
Free Radic Biol Med ; 51(3): 688-99, 2011 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-21640818

RESUMEN

Redox regulation is critical for a number of cellular functions and has been implicated in the etiology and progression of several diseases, such as cardiovascular diseases, neurodegenerative diseases, and cancer. It has been shown that, in the absence of gamma-interferon inducible lysosomal thiol reductase (GILT), cells are under increased oxidative stress with higher superoxide levels and decreased stability, expression, and function of mitochondrial manganese superoxide dismutase (SOD2). Here, we further elucidate the role of GILT in the homeostatic regulation of oxidative stress. We show that GILT-deficient fibroblasts exhibit reduced glutathione levels, shift in GSSG/GSH ratio toward the oxidized form, and accumulate dysfunctional mitochondria. Redox-sensitive pathways involving Erk1/2 activation and nuclear high mobility group box 1 (HMGB1) protein cytosolic translocation are both activated and associated with increased autophagy in GILT-/- fibroblasts. We hypothesize that these events are responsible for degrading the damaged mitochondria and mitochondrial SOD2 in the absence of GILT. This is the first time to our knowledge that a lysosomal enzyme has been implicated in global effects within the cell.


Asunto(s)
Fibroblastos/metabolismo , Glutatión/metabolismo , Lisosomas/metabolismo , Mitocondrias/metabolismo , Oxidorreductasas/metabolismo , Animales , Autofagia/genética , Línea Celular Transformada , Retroalimentación Fisiológica , Fibroblastos/patología , Proteína HMGB1/metabolismo , Homeostasis , Lisosomas/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/patología , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Oxidación-Reducción , Estrés Oxidativo/genética , Oxidorreductasas/genética , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro , Transducción de Señal/genética
9.
Biochem Biophys Res Commun ; 306(4): 937-42, 2003 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-12821132

RESUMEN

GTP cyclohydrolase I (GCH, EC 3.5.4.16) regulates the level of tetrahydrobiopterin and in turn the activities of nitric oxide synthase and aromatic amino acid hydroxylases. Type II GCH mRNA, an alternatively spliced species abundant in blood cells, encodes a truncated and nonfunctional protein. When we stimulate peripheral blood mononuclear cells by PHA, the transcription of full-length GCH mRNA increased, but that of type II mRNA decreased transiently. We further demonstrated that the type II cDNA exerted a dominant-negative effect on the wild-type cDNA, similar to the effect of some GCH mutants. Therefore, type II mRNA may regulate GCH and then contribute to the regulation of NO production by BH4-dependent iNOS in mononuclear cells. Selection of the splicing sites may be coupled with transcriptional activation of the GCH gene.


Asunto(s)
GTP Ciclohidrolasa/biosíntesis , Regulación Enzimológica de la Expresión Génica , Leucocitos Mononucleares/enzimología , Empalme Alternativo , Western Blotting , Línea Celular , ADN Complementario/metabolismo , Relación Dosis-Respuesta a Droga , GTP Ciclohidrolasa/química , GTP Ciclohidrolasa/genética , Genes Dominantes , Humanos , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo II , Plásmidos/metabolismo , Reacción en Cadena de la Polimerasa , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Tiempo , Transcripción Genética , Transfección , Células Tumorales Cultivadas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA