RESUMEN
G protein-coupled receptors (GPCRs) regulate many cellular processes in response to various stimuli, including light, hormones, neurotransmitters, and odorants, some of which play critical roles in innate and adaptive immune responses. However, the physiological functions of many GPCRs and the involvement of them in autoimmune diseases of the central nervous system remain unclear. Here, we demonstrate that GPR141, an orphan GPCR belonging to the class A receptor family, suppresses immune responses. High GPR141 messenger RNA levels were expressed in myeloid-lineage cells, including neutrophils (CD11b + Gr1+), monocytes (CD11b + Gr1-Ly6C+ and CD11b + Gr1-Ly6C-), macrophages (F4/80+), and dendritic cells (CD11c+). Gpr141 -/- mice, which we independently generated, displayed almost no abnormalities in myeloid cell differentiation and compartmentalization in the spleen and bone marrow under steady-state conditions. However, Gpr141 deficiency exacerbated disease conditions of experimental autoimmune encephalomyelitis, an autoimmune disease model for multiple sclerosis, with increased inflammation in the spinal cord. Gpr141 -/- mice showed increased CD11b + Gr1+ neutrophils, CD11b + Gr1- monocytes, CD11c+ dendritic cells, and CD4+ T cell infiltration into the experimental autoimmune encephalomyelitis-induced spinal cord compared with littermate control mice. Lymphocytes enriched from Gpr141 -/- mice immunized with myelin oligodendrocyte glycoprotein 35-55 produced high amounts of interferon-γ, interleukin-17A, and interleukin-6 compared with those from wild-type mice. Moreover, CD11c+ dendritic cells (DCs) purified from Gpr141 -/- mice increased cytokine production of myelin oligodendrocyte glycoprotein 35-55-specific T cells. These findings suggest that GPR141 functions as a negative regulator of immune responses by controlling the functions of monocytes and dendritic cells and that targeting GPR141 may be a possible therapeutic intervention for modulating chronic inflammatory diseases.
Asunto(s)
Encefalomielitis Autoinmune Experimental , Inflamación , Ratones Noqueados , Células Mieloides , Receptores Acoplados a Proteínas G , Animales , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/deficiencia , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Encefalomielitis Autoinmune Experimental/metabolismo , Células Mieloides/metabolismo , Células Mieloides/inmunología , Inflamación/inmunología , Inflamación/metabolismo , Ratones , Ratones Endogámicos C57BL , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Glicoproteína Mielina-Oligodendrócito/inmunología , Fragmentos de PéptidosRESUMEN
Theiler's murine encephalomyelitis virus (TMEV) causes a chronic demyelinating disease similar to multiple sclerosis in mice. Although sialic acids have been shown to be essential for TMEV attachment to the host, the surface receptor has not been identified. While type I interferons play a pivotal role in the elimination of the chronic infectious Daniel (DA) strain, the role of plasmacytoid dendritic cells (pDCs) is controversial. We herein found that TMEV binds to conventional DCs but not to pDCs. A glycomics analysis showed that the sialylated N-glycan fractions were lower in pDCs than in conventional DCs, indicating that pDCs are not susceptible to TMEV infection due to the low levels of sialic acid. TMEV capsid proteins contain an integrin recognition motif, and dot blot assays showed that the integrin proteins bind to TMEV and that the viral binding was reduced in the desialylated αX ß2 . αX ß2 protein suppressed TMEV replication in vivo, and TMEV co-localized with integrin αM at the cell membrane and TLR 3 in the cytoplasm, suggesting that αM serves as the viral attachment and entry. These results show that the chronic encephalomyelitis virus utilizes sialylated integrins as cell surface receptors, leading to cellular tropism to evade pDC activation.
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Encefalomielitis , Integrinas , Ratones , Animales , Receptores de Superficie Celular , Células Dendríticas , TropismoRESUMEN
Dendritic cell immunoreceptor (DCIR) is an inhibitory C-type lectin receptor that acts as a negative regulator in the immune system and bone metabolism. We previously revealed that DCIR deficiency enhanced osteoclastogenesis and antigen presentation of dendritic cells, and that asialo-biantennary N-glycan (NA2) functions as a ligand for DCIR. NA2 binding to DCIR suppressed murine and human osteoclastogenesis that occurs in the presence of M-CSF and RANKL. The DCIR-NA2 axis, therefore, plays an important role in regulating osteoclastogenesis in both mice and humans, although the underlying mechanisms remain unclear. Here we found that Dcir -/- bone marrow-derived macrophages (BMMs) exhibited greater proliferative and differentiation responses to M-CSF and RANKL, respectively, than wild-type (WT) BMMs. Moreover, Dcir -/- osteoclasts (OCs) increased resorptive activity and cell fusion more significantly than WT OCs. DCIR deficiency affects gene expression patterns in OCs, and we found that the expression of neuraminidase 4 was increased in Dcir -/- OCs. Furthermore, DCIR-NA2 interaction in WT BMMs, but not Dcir -/- BMMs, decreased Akt phosphorylation in response to M-CSF and RANKL. These data suggest that DCIR regulates osteoclastogenesis by downregulating M-CSF and RANKL signaling, and that DCIR-mediated signaling may contribute to the terminal modification of oligosaccharides by controlling the expression of glycosylation enzymes.
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Resorción Ósea , Factor Estimulante de Colonias de Macrófagos , Animales , Humanos , Ratones , Resorción Ósea/metabolismo , Proliferación Celular , Factor Estimulante de Colonias de Macrófagos/farmacología , Factor Estimulante de Colonias de Macrófagos/metabolismo , Osteoclastos/metabolismo , Transducción de SeñalRESUMEN
Clec1A, a member of C-type lectin receptor family, has a carbohydrate recognition domain in its extracellular region, but no known signaling motif in the cytoplasmic domain. Clec1a is highly expressed in endothelial cells and weakly in dendritic cells. Although this molecule was reported to play an important role in the host defense against Aspergillus fumigatus by recognizing 1,8-dihydroxynaphthalene-melanin on the fungal surface, the roles of this molecule in un-infected animals remain to be elucidated. In this study, we found that Clec1a-/- mice develop milder symptoms upon induction of experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. The maximum disease score was significantly lower, and demyelination and inflammation of the spinal cord were much milder in Clec1a-/- mice compared to wild-type mice. No abnormality was detected in the immune cell composition in the draining lymph nodes and spleen on day 10 and 16 after EAE induction. Recall memory T cell proliferation after restimulation with myelin oligodendrocyte glycoprotein peptide (MOG35-55) in vitro was decreased in Clec1a-/- mice, and antigen presenting ability of Clec1a-/- dendritic cells was impaired. Interestingly, RNA-Seq and RT-qPCR analyses clearly showed that the expression of inflammatory cytokines including Il17a, Il6 and Il1b was greatly decreased in Clec1a-/- mice after induction of EAE, suggesting that this reduced cytokine production is responsible for the amelioration of EAE in Clec1a-/- mice. These observations suggest a novel function of Clec1A in the immune system.
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Presentación de Antígeno , Células Dendríticas , Encefalomielitis Autoinmune Experimental , Interleucina-17 , Lectinas Tipo C , Animales , Citocinas/metabolismo , Células Dendríticas/metabolismo , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Células Endoteliales/metabolismo , Interleucina-17/metabolismo , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Ratones , Ratones Endogámicos C57BLRESUMEN
Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor with a carbohydrate recognition domain and an immunoreceptor tyrosine-based inhibitory motif. Previously, we showed that Dcir-/- mice spontaneously develop autoimmune enthesitis and sialadenitis, and also develop metabolic bone abnormalities. However, the ligands for DCIR functionality remain to be elucidated. Here we showed that DCIR is expressed on osteoclasts and DCs and binds to an asialo-biantennary N-glycan(s) (NA2) on bone cells and myeloid cells. Osteoclastogenesis was enhanced in Dcir-/- cells, and NA2 inhibited osteoclastogenesis. Neuraminidase treatment, which exposes excess NA2 by removing the terminal sialic acid of N-glycans, suppressed osteoclastogenesis and DC function. Neuraminidase treatment of mice ameliorated collagen-induced arthritis and experimental autoimmune encephalomyelitis in a DCIR-dependent manner, due to suppression of antigen presentation by DCs. These results suggest that DCIR activity is regulated by the modification of the terminal sialylation of biantennary N-glycans, and this interaction is important for the control of both autoimmune and bone metabolic diseases.
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Células Dendríticas/fisiología , Lectinas Tipo C/metabolismo , Glicoproteínas de Membrana/metabolismo , Osteoclastos/metabolismo , Osteogénesis/fisiología , Polisacáridos/metabolismo , Receptores Inmunológicos/metabolismo , Animales , Artritis Experimental/inducido químicamente , Artritis Experimental/tratamiento farmacológico , Células Cultivadas , Células Dendríticas/inmunología , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Células HEK293 , Humanos , Lectinas Tipo C/genética , Glicoproteínas de Membrana/genética , Ratones Endogámicos C57BL , Ratones Mutantes , Ratones Transgénicos , N-Acetilglucosaminiltransferasas/genética , N-Acetilglucosaminiltransferasas/metabolismo , Neuraminidasa/metabolismo , Neuraminidasa/farmacología , Receptores Inmunológicos/genéticaRESUMEN
INTRODUCTION: The present study showed the involvement of immunosuppressive myeloid-derived suppressor cells during the disease progression in a 69-year-old man with a prostate cancer. CASE PRESENTATION: The patient with metastatic PC (cT4N1M1ab) was initially treated with primary androgen deprivation therapy for 5 months and then chemotherapy with docetaxel, but he expired at the 8th month. In order to investigate whether myeloid-derived suppressor cells are implicated in the cancer exacerbation during androgen deprivation therapy, we assessed the long-term changes in peripheral blood myeloid-derived suppressor cell fractions by using flow cytometry. While prostate-specific antigen levels decreased after androgen deprivation therapy, the population of each myeloid-derived suppressor cell subsets increased during disease deterioration. CONCLUSION: Increase in myeloid-derived suppressor cells populations was correlated with prostate cancer progression.
RESUMEN
TARM1 is a member of the leukocyte immunoglobulin-like receptor family and stimulates macrophages and neutrophils in vitro by associating with FcRγ. However, the function of this molecule in the regulation of the immune system is unclear. Here, we show that Tarm1 expression is elevated in the joints of rheumatoid arthritis mouse models, and the development of collagen-induced arthritis (CIA) is suppressed in Tarm1-/- mice. T cell priming against type 2 collagen is suppressed in Tarm1-/- mice and antigen-presenting ability of GM-CSF-induced dendritic cells (GM-DCs) from Tarm1-/- mouse bone marrow cells is impaired. We show that type 2 collagen is a functional ligand for TARM1 on GM-DCs and promotes DC maturation. Furthermore, soluble TARM1-Fc and TARM1-Flag inhibit DC maturation and administration of TARM1-Fc blocks the progression of CIA in mice. These results indicate that TARM1 is an important stimulating factor of dendritic cell maturation and could be a good target for the treatment of autoimmune diseases.
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Artritis Experimental/metabolismo , Artritis Experimental/patología , Colágeno/metabolismo , Células Dendríticas/patología , Receptores Inmunológicos/metabolismo , Animales , Presentación de Antígeno , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Proteínas Fluorescentes Verdes/metabolismo , Inmunización , Ligandos , Ratones Endogámicos C57BL , Receptores Inmunológicos/deficienciaRESUMEN
BACKGROUND: As a member of peroxiredoxin (PRX) family, PRX3 is predominantly located in mitochondria and plays an important role of free radical scavenging. Since a body of evidence demonstrated the involvement of PRX3 in insulin secretion, insulin sensitivity, and glucose metabolism, the present study was conducted to investigate the role of PRX3 in the pathogenesis of polycystic ovarian syndrome (PCOS) featured in insulin resistance. METHODS: Enzyme-linked immunosorbent assay was performed to detect plasma PRX3 in PCOS patients and control subjects. Levels of reactive oxygen species (ROS) and oxidized PRXs were detected in mouse islet cells treated with gradient glucose. RESULTS: We did not find significant difference of fasting plasma PRX3 between PCOS patients and controls. No association was noticed between fasting plasma PRX3 and fasting plasma glucose or insulin. After oral glucose tolerance test (OGTT), PCOS patients showed higher levels of both glucose and insulin as compared to controls. The plasma level of PRX3 was significantly increased at 2 h and began to fall back at 3 h of OGTT. There was a one-hour time lag of peak values between plasma PRX3 and insulin, and the plasma PRX3 at 2 h was positively correlated with the insulin level at 1 h of OGTT of PCOS patients. In addition, the level of ROS was significantly elevated at 1 h and oxidized PRX3 was increased dramatically at 2 h of 16.7mM glucose stimulation in mouse islet cells. CONCLUSION: It seems that PRX3 does not show its antioxidant function under baseline conditions. Instead, PRX3 responds to oxidative stress induced by rapid increase of insulin and glucose in patients with PCOS.
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Resistencia a la Insulina , Islotes Pancreáticos/metabolismo , Peroxiredoxina III/sangre , Síndrome del Ovario Poliquístico/sangre , Estudios de Casos y Controles , Células Cultivadas , Femenino , Glucosa/farmacología , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/metabolismo , Islotes Pancreáticos/citología , Islotes Pancreáticos/efectos de los fármacos , Obesidad/fisiopatología , Síndrome del Ovario Poliquístico/patología , Edulcorantes/farmacologíaRESUMEN
Receptors for the Fc domain of immunoglobulins [Fc receptors (FcRs)] are essential for the maintenance of antibody-mediated immune responses. FcRs consist of activating- and inhibitory-type receptors that regulate adequate thresholds for various immune cells. In particular, polymorphisms and/or gene copy-number variations of FcRs for IgG (FcγRs) are closely associated with the development of inflammatory disorders, including autoimmune diseases. Recent evidence has implicated polymorphisms of FcRs in the efficacy of monoclonal antibody (mAb)-mediated therapy. This review provides an overview of genetic variations in human FcγRs and the clinical contribution of FcγR polymorphisms in mAb treatments for cancer, autoimmune diseases and allergies.
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Antineoplásicos Inmunológicos/uso terapéutico , Enfermedades Autoinmunes/terapia , Hipersensibilidad/terapia , Inmunoterapia/métodos , Neoplasias/terapia , Receptores Fc/genética , Animales , Enfermedades Autoinmunes/inmunología , Humanos , Hipersensibilidad/inmunología , Inmunidad Humoral , Neoplasias/inmunología , Polimorfismo GenéticoRESUMEN
As a member of peroxiredoxin family, peroxiredoxin-3 plays a major role in the control of mitochondrial level of reactive oxygen species. During the breeding of experimental mice, we noticed that the peroxiredoxin-3 knockout mice were listless with aging. In the present study, we compared the swimming exercise performance and oxidative status between peroxiredoxin-3 knockout mice (n = 15) and wild-type littermates (n = 15). At the age of 10 months, the physical strength of peroxiredoxin-3 knockout mice was much lower than the wild-type littermates. Increased oxidative damage and decreased mitochondrial DNA copy number of the animal skeletal muscles were observed in peroxiredoxin-3 knockout mice as compared to that in the wild-type littermates. In addition, we found increased apoptotic cells in the brains of peroxiredoxin-3 knockout mice. Our results suggest that the deficiency of peroxiredoxin-3 induces accelerated oxidative stress and mitochondrial impairment, resulting in the decrease of energy supply and cellular activities. Peroxiredoxin-3 might be involved in the inhibition of aging process.
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Fuerza Muscular/genética , Peroxiredoxina III/fisiología , Envejecimiento/metabolismo , Envejecimiento/patología , Envejecimiento/fisiología , Animales , Apoptosis/genética , Biomarcadores/metabolismo , Variaciones en el Número de Copia de ADN , Genotipo , Ratones Noqueados , Mitocondrias/metabolismo , Estrés Oxidativo , Peroxiredoxina III/genética , Peroxiredoxina III/metabolismo , Especies Reactivas de Oxígeno/metabolismoAsunto(s)
Anquilosis/inmunología , Presentación de Antígeno/genética , Huesos/metabolismo , Células Dendríticas/inmunología , Lectinas Tipo C/genética , Animales , Anquilosis/patología , Presentación de Antígeno/inmunología , Densidad Ósea/genética , Huesos/citología , Lectinas Tipo C/inmunología , Ratones , Ratones NoqueadosRESUMEN
Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor containing a carbohydrate recognition domain in its extracellular portion and an immunoreceptor tyrosinebased inhibitory motif, which transduces negative signals into cells, in its cytoplasmic portion. Previously, we showed that Dcir(/) mice spontaneously develop autoimmune diseases such as enthesitis and sialadenitis due to excess expansion of dendritic cells (DCs), suggesting that DCIR is critically important for the homeostasis of the immune system. In this report, we analyzed the role of DCIR in the development of experimental autoimmune encephalomyelitis (EAE), an autoimmune disease model for multiple sclerosis. We found that EAE was exacerbated in Dcir(/) mice associated with severe demyelination of the spinal cords. The number of infiltrated CD11c(+) DCs and CD4(+) T cells into spinal cords was increased in Dcir(/) mice. Recall proliferative response of lymph node cells was higher in Dcir(/) mice compared with wild-type mice. These observations suggest that DCIR is an important negative regulator of the immune system, and Dcir(/) mice should be useful for analyzing the roles of DCIR in an array of autoimmune diseases.
Asunto(s)
Encefalomielitis Autoinmune Experimental/inmunología , Lectinas Tipo C/inmunología , Esclerosis Múltiple/inmunología , Receptores Inmunológicos/inmunología , Transducción de Señal/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Enfermedades Desmielinizantes/inmunología , Células Dendríticas/inmunología , Células Dendríticas/patología , Progresión de la Enfermedad , Lectinas Tipo C/química , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Ratones Endogámicos C57BL , Ratones Transgénicos , Receptores Inmunológicos/química , Médula Espinal/inmunología , Médula Espinal/patologíaRESUMEN
Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor mainly expressed in DCs. Dcir (-/-) mice spontaneously develop autoimmune enthesitis and ankylosis accompanied by fibrocartilage proliferation and ectopic ossification. However, the mechanisms of new bone/cartilage formation in Dcir (-/-) mice remain to be elucidated. In this study, we show that DCIR maintains bone homeostasis by regulating IFN-γ production under pathophysiological conditions. DCIR deficiency increased bone volume in femurs and caused aberrant ossification in joints, whereas these symptoms were abolished in Rag2(-/-)Dcir(-/-) mice. IFN-γ-producing T cells accumulated in lymph nodes and joints of Dcir(-/-) mice, and purified Dcir(-/-) DCs enhanced IFN-γ(+) T cell differentiation. The ankylotic changes and bone volume increase were suppressed in the absence of IFN-γ. Thus, IFN-γ is a positive chondrogenic and osteoblastogenic factor, and DCIR is a crucial regulator of bone metabolism; consequently, both factors are potential targets for therapies directed against bone metabolic diseases.
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Huesos/metabolismo , Homeostasis/genética , Homeostasis/inmunología , Interferón gamma/biosíntesis , Lectinas Tipo C/genética , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Factores de Edad , Animales , Anquilosis/diagnóstico por imagen , Anquilosis/genética , Anquilosis/inmunología , Anquilosis/patología , Densidad Ósea/genética , Huesos/diagnóstico por imagen , Huesos/patología , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Condrocitos/citología , Condrocitos/metabolismo , Proteínas de Unión al ADN/deficiencia , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Masculino , Ratones , Ratones Noqueados , Osteoblastos/citología , Osteoblastos/metabolismo , Subgrupos de Linfocitos T/citología , Microtomografía por Rayos XRESUMEN
The spleen is a lymphoid organ that serves as a unique niche for immune reactions, extramedullary hematopoiesis, and the removal of aged erythrocytes from the circulation. While much is known about the immunological functions of the spleen, the mechanisms governing the development and organization of its stromal microenvironment remain poorly understood. Here we report the generation and analysis of a Tlx1(Cre) (ER) (-Venus) knock-in mouse strain engineered to simultaneously express tamoxifen-inducible CreER(T2) and Venus fluorescent protein under the control of regulatory elements of the Tlx1 gene, which encodes a transcription factor essential for spleen development. We demonstrated that Venus as well as CreER expression recapitulates endogenous Tlx1 transcription within the spleen microenvironment. When Tlx1(Cre) (ER) (-Venus) mice were crossed with the Cre-inducible reporter strain, Tlx1-expressing cells as well as their descendants were specifically labeled following tamoxifen administration. We also showed by cell lineage tracing that asplenia caused by Tlx1 deficiency is attributable to altered contribution of mesenchymal cells in the spleen anlage to the pancreatic mesenchyme. Thus, Tlx1(Cre) (ER) (-Venus) mice represent a new tool for lineage tracing and conditional gene manipulation of spleen mesenchymal cells, essential approaches for understanding the molecular mechanisms of spleen development.
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Técnicas de Sustitución del Gen/métodos , Proteínas de Homeodominio/genética , Células Madre Mesenquimatosas/metabolismo , Modelos Animales , Morfogénesis/fisiología , Bazo/embriología , Animales , Proteínas Bacterianas/metabolismo , Linaje de la Célula/fisiología , Cruzamientos Genéticos , Cartilla de ADN/genética , Citometría de Flujo , Proteínas de Homeodominio/metabolismo , Inmunohistoquímica , Integrasas/metabolismo , Proteínas Luminiscentes/metabolismo , Ratones , Microscopía Fluorescente , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Bazo/citología , TamoxifenoRESUMEN
Natural killer (NK) cells are lymphocytes of the innate immune system that sense target cells through a panel of activating and inhibitory receptors. Together with NKG2D, the natural cytotoxicity receptors (NCRs) are major activating receptors involved in tumor cell detection. Although numerous NKG2D ligands have been identified, characterization of the molecules interacting with the NCRs is still incomplete. The identification of B7-H6 as a counter structure of the NCR NKp30 shed light on the molecular basis of NK cell immunosurveillance. We review here the current knowledge on NKp30 and B7-H6, and we discuss their potential role in anti-tumor immunity.
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Antígenos B7/metabolismo , Células Asesinas Naturales/metabolismo , Receptor 3 Gatillante de la Citotoxidad Natural/metabolismo , Neoplasias/metabolismo , Antígenos B7/química , Antígenos B7/genética , Humanos , Células Asesinas Naturales/inmunología , Monitorización Inmunológica , Receptor 3 Gatillante de la Citotoxidad Natural/química , Receptor 3 Gatillante de la Citotoxidad Natural/genética , Neoplasias/inmunología , Mapeo de Interacción de ProteínasRESUMEN
Cells in the immune system are regulated positively or negatively by sets of receptor pairs that conduct balanced, activating, or inhibitory intracellular signaling. One such receptor pair termed paired Ig-like receptor (PIR) is composed of the inhibitory PIR-B and its activating isoform, PIR-A. Upon binding to their shared ligand, MHC class I molecules, these receptors control the threshold for immune cell activation. Gene-targeting studies on PIR-B in mice revealed the importance of the inhibition mediated by the PIR-B-MHC interaction in the immune system. Recent studies also revealed the significance of the interaction of PIR-B with neurite outgrowth inhibitors, including Nogo in the CNS. The coordinated regulation by PIR-B and PIR-A is considered to be primarily dependent on their expression balance in cells. However, the mechanism underlying transcriptional control of the genes for PIR-B and PIR-A (Pirb and Pira, respectively) remains to be clarified. In this study, we identified the major cis-acting promoter segment for Pirb and Pira in B cells as the -212 to -117 region upstream from the translation initiation codon. PU.1 and Runx3 were found to bind to this Pirb promoter. Truncation of the PU.1-binding motif significantly reduced the promoter activity, whereas the influence of elimination of the Runx3 site was marginal in B lymphoma BCL1-B20 cells. Unexpectedly, PU.1, but not Runx3, knockdown reduced the levels of both the Pirb and Pira transcripts. We conclude that the major promoter of Pirb, and probably Pira as well, is activated dominantly by PU.1 and marginally by Runx3 in B cells.
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Linfocitos B/metabolismo , Subunidad alfa 3 del Factor de Unión al Sitio Principal/genética , Proteínas Proto-Oncogénicas/genética , Receptores Inmunológicos/genética , Transactivadores/genética , Activación Transcripcional/genética , Animales , Sitios de Unión , Línea Celular Tumoral , Subunidad alfa 3 del Factor de Unión al Sitio Principal/fisiología , Linfoma de Células B/genética , Ratones , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Proto-Oncogénicas/fisiología , Transactivadores/fisiologíaRESUMEN
Cancer development is often associated with the lack of specific and efficient recognition of tumor cells by the immune system. Natural killer (NK) cells are lymphocytes of the innate immune system that participate in the elimination of tumors. We report the identification of a tumor cell surface molecule that binds NKp30, a human receptor which triggers antitumor NK cell cytotoxicity and cytokine secretion. This previously unannotated gene belongs to the B7 family and, hence, was designated B7-H6. B7-H6 triggers NKp30-mediated activation of human NK cells. B7-H6 was not detected in normal human tissues but was expressed on human tumor cells, emphasizing that the expression of stress-induced self-molecules associated with cell transformation serves as a mode of cell recognition in innate immunity.
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Antígenos CD/inmunología , Antígeno B7-1/inmunología , Células Asesinas Naturales/inmunología , Ligandos , Activación de Linfocitos , Receptor 3 Gatillante de la Citotoxidad Natural/inmunología , Secuencia de Aminoácidos , Animales , Antígenos CD/genética , Antígenos de Superficie/inmunología , Antígenos B7 , Antígeno B7-1/genética , Línea Celular Tumoral/inmunología , Femenino , Humanos , Inmunidad Innata/inmunología , Fragmentos Fc de Inmunoglobulinas/genética , Fragmentos Fc de Inmunoglobulinas/inmunología , Células K562 , Células Asesinas Naturales/citología , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Receptor 3 Gatillante de la Citotoxidad Natural/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/inmunologíaRESUMEN
As a mitochondrial scavenger of reactive oxygen species (ROS), peroxiredoxin III (PrxIII) plays an important role in regulating intracellular ROS level. We previously found that PrxIII knockout (PrxIII(-/-)) mice were more sensitive than wild-type (PrxIII(+/+)) controls to intratracheal inoculation of lipopolysaccharide (LPS), but the precise mechanism remained to be obscure. In the present study, we detected the levels of ROS and tumour necrosis factor alpha (TNF-alpha) in mouse bone-marrow-derived macrophages. LPS stimulation induced transient increase of ROS production and augmentation of TNF-alpha accumulation in PrxIII(-/-) macrophages. In addition, we observed reduced viability and increased apoptosis in PrxIII(-/-) macrophages exposed to LPS. Our results provide direct evidence that PrxIII is necessary for macrophages to protect against LPS-induced oxidative stress.
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Macrófagos/metabolismo , Estrés Oxidativo , Peroxirredoxinas/deficiencia , Animales , Western Blotting , Supervivencia Celular/efectos de los fármacos , Lipopolisacáridos/farmacología , Macrófagos/citología , Macrófagos/efectos de los fármacos , Ratones , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Azul de Tripano , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Type 1 diabetes mellitus (T1D) in humans is an organ-specific autoimmune disease in which pancreatic islet beta cells are ruptured by autoreactive T cells. NOD mice, the most commonly used animal model of T1D, show early infiltration of leukocytes in the islets (insulitis), resulting in islet destruction and diabetes later. NOD mice produce various islet beta cell-specific autoantibodies, although it remains a subject of debate regarding whether these autoantibodies contribute to the development of T1D. Fc gammaRs are multipotent molecules that play important roles in Ab-mediated regulatory as well as effector functions in autoimmune diseases. To investigate the possible role of Fc gammaRs in NOD mice, we generated several Fc gammaR-less NOD lines, namely FcR common gamma-chain (Fc Rgamma)-deficient (NOD.gamma(-/-)), Fc gammaRIII-deficient (NOD.III(-/-)), Fc gammaRIIB-deficient (NOD.IIB(-/-)), and both Fc Rgamma and Fc gammaRIIB-deficient NOD (NOD.null) mice. In this study, we show significant protection from diabetes in NOD.gamma(-/-), NOD.III(-/-), and NOD.null, but not in NOD.IIB(-/-) mice even with grossly comparable production of autoantibodies among them. Insulitis in NOD.gamma(-/-) mice was also alleviated. Adoptive transfer of bone marrow-derived dendritic cells or NK cells from NOD mice rendered NOD.gamma(-/-) animals more susceptible to diabetes, suggesting a possible scenario in which activating Fc gammaRs on dendritic cells enhance autoantigen presentation leading to the activation of autoreactive T cells, and Fc gammaRIII on NK cells trigger Ab-dependent effector functions and inflammation. These findings highlight the critical roles of activating Fc gammaRs in the development of T1D, and indicate that Fc gammaRs are novel targets for therapies for T1D.
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Células Dendríticas/inmunología , Diabetes Mellitus Tipo 1/inmunología , Receptores de IgG/inmunología , Traslado Adoptivo , Animales , Autoanticuerpos/inmunología , Autoantígenos/inmunología , Diabetes Mellitus Tipo 1/prevención & control , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Inmunoglobulinas Intravenosas/uso terapéutico , Inmunohistoquímica , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/patología , Células Asesinas Naturales/inmunología , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos NOD , Receptores de IgG/deficiencia , Receptores de IgG/genética , Linfocitos T/inmunologíaRESUMEN
MER5 (also called peroxiredoxin III, PrxIII) is a member of peroxiredoxin family that has antioxidant activity. The present study was performed to investigate its in vivo function using MER5 knockout mice. MER5 knockout mice were born in normal frequency and could grow to maturity, but we found that intracellular ROS levels are significantly higher in the macrophages of the knockout mice. We examined roles of MER5 function for the oxidative stress responses by intratracheal inoculation of lipopolysaccharide (LPS) to the mice. Lung inflammation such as inflammatory cell infiltration and airway wall thickening was more severely detected in the knockout mice. At the same time, oxidative damage on DNA and proteins was more strongly detected in lung tissues of the knockout mice, including 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation and protein carbonylation. The degrees of lung inflammation and oxidative damage were positively related with LPS doses. Our results indicate that MER5 knockout mice accumulated higher intracellular ROS levels, which cause LPS-induced lung injury more severely, and thus, suggested that MER5 acts as an important scavenger of reactive oxygen species (ROS) under oxidative stress.