RESUMO
Monocyte-derived macrophages, the major source of pathogenic macrophages in COVID-19, are oppositely instructed by macrophage CSF (M-CSF) or granulocyte macrophage CSF (GM-CSF), which promote the generation of antiinflammatory/immunosuppressive MAFB+ (M-MØ) or proinflammatory macrophages (GM-MØ), respectively. The transcriptional profile of prevailing macrophage subsets in severe COVID-19 led us to hypothesize that MAFB shapes the transcriptome of pulmonary macrophages driving severe COVID-19 pathogenesis. We have now assessed the role of MAFB in the response of monocyte-derived macrophages to SARS-CoV-2 through genetic and pharmacological approaches, and we demonstrate that MAFB regulated the expression of the genes that define pulmonary pathogenic macrophages in severe COVID-19. Indeed, SARS-CoV-2 potentiated the expression of MAFB and MAFB-regulated genes in M-MØ and GM-MØ, where MAFB upregulated the expression of profibrotic and neutrophil-attracting factors. Thus, MAFB determines the transcriptome and functions of the monocyte-derived macrophage subsets that underlie pulmonary pathogenesis in severe COVID-19 and controls the expression of potentially useful biomarkers for COVID-19 severity.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , COVID-19/metabolismo , Macrófagos/metabolismo , Macrófagos Alveolares/metabolismo , Biomarcadores/metabolismo , Fator de Transcrição MafB/genética , Fator de Transcrição MafB/metabolismoRESUMO
Large constellations of bright artificial satellites in low Earth orbit pose significant challenges to ground-based astronomy1. Current orbiting constellation satellites have brightnesses between apparent magnitudes 4 and 6, whereas in the near-infrared Ks band, they can reach magnitude 2 (ref. 2). Satellite operators, astronomers and other users of the night sky are working on brightness mitigation strategies3,4. Radio emissions induce further potential risk to ground-based radio telescopes that also need to be evaluated. Here we report the outcome of an international optical observation campaign of a prototype constellation satellite, AST SpaceMobile's BlueWalker 3. BlueWalker 3 features a 64.3 m2 phased-array antenna as well as a launch vehicle adaptor (LVA)5. The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky. Additionally, the LVA reached an apparent V-band magnitude of 5.5, four times brighter than the current International Astronomical Union recommendation of magnitude 7 (refs. 3,6); it jettisoned on 10 November 2022 (Universal Time), and its orbital ephemeris was not publicly released until 4 days later. The expected build-out of constellations with hundreds of thousands of new bright objects1 will make active satellite tracking and avoidance strategies a necessity for ground-based telescopes.
RESUMO
Toll-like receptor 7 (TLR7) is an endosomal pathogen-associated molecular pattern (PAMP) receptor that senses single-stranded RNA (ssRNA) and whose engagement results in the production of type I IFN and pro-inflammatory cytokines upon viral exposure. Recent genetic studies have established that a dysfunctional TLR7-initiated signaling is directly linked to the development of inflammatory responses. We present evidence that TLR7 is preferentially expressed by monocyte-derived macrophages generated in the presence of M-CSF (M-MØ). We now show that TLR7 activation in M-MØ triggers a weak MAPK, NFκB, and STAT1 activation and results in low production of type I IFN. Of note, TLR7 engagement reprograms MAFB+ M-MØ towards a pro-inflammatory transcriptional profile characterized by the expression of neutrophil-attracting chemokines (CXCL1-3, CXCL5, CXCL8), whose expression is dependent on the transcription factors MAFB and AhR. Moreover, TLR7-activated M-MØ display enhanced pro-inflammatory responses and a stronger production of neutrophil-attracting chemokines upon secondary stimulation. As aberrant TLR7 signaling and enhanced pulmonary neutrophil/lymphocyte ratio associate with impaired resolution of virus-induced inflammatory responses, these results suggest that targeting macrophage TLR7 might be a therapeutic strategy for viral infections where monocyte-derived macrophages exhibit a pathogenic role.
Assuntos
Monócitos , Receptor 7 Toll-Like , Humanos , Receptor 7 Toll-Like/metabolismo , Monócitos/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Infiltração de Neutrófilos , Citocinas/metabolismo , Macrófagos/metabolismo , Quimiocinas/metabolismoRESUMO
Hyperactivity in the sympathetic nervous system has been shown to be related to the development of ovarian pathologies. In addition, obesity has been found to be associated with multiple reproductive anomalies and is considered a chronic stress condition of low intensity with changes in the peripheral sympathetic activity. Therefore, in the present study, we aimed to evaluate if the information reaching the ovaries through the superior ovarian nerve (SON) modifies the ovarian function of Zucker fatty rats. We performed a unilateral section of the SON at 32 days of age and autopsies were carried out on the day of the first vaginal estrus. The results showed that fatty animals do not ovulate on the day of the first vaginal estrus and exhibit an increase in catecholaminergic fibers and the presence of precystic structures in the ovaries, without changes in the onset of puberty or in the secretion of ovarian and hypophyseal hormones. We also found that the section of the right SON resulted in ovulation on the day of the first vaginal estrus, which was accompanied by a decrease in ovarian noradrenaline content. The section of the left SON caused a delay in puberty without changes in the rest of the parameters. These results provide functional evidence that the peripheral sympathetic innervation participates in the regulation of ovarian functions in an animal model of genetic obesity.
Assuntos
Tecido Nervoso/fisiologia , Ovário/inervação , Ovulação/fisiologia , Animais , Catecolaminas/metabolismo , Feminino , Ovário/anatomia & histologia , Ratos Zucker , Maturidade Sexual/fisiologiaRESUMO
Defective IFN production and exacerbated inflammatory and pro-fibrotic responses are hallmarks of SARS-CoV-2 infection in severe COVID-19. Based on these hallmarks, and considering the pivotal role of macrophages in COVID-19 pathogenesis, we hypothesize that the transcription factors MAFB and MAF critically contribute to COVID-19 progression by shaping the response of macrophages to SARS-CoV-2. Our proposal stems from the recent identification of pathogenic lung macrophage subsets in severe COVID-19, and takes into consideration the previously reported ability of MAFB to dampen IFN type I production, as well as the critical role of MAFB and MAF in the acquisition and maintenance of the transcriptional signature of M-CSF-conditioned human macrophages. Solid evidences are presented that link overexpression of MAFB and silencing of MAF expression with clinical and biological features of severe COVID-19. As a whole, we propose that a high MAFB/MAF expression ratio in lung macrophages could serve as an accurate diagnostic tool for COVID-19 progression. Indeed, reversing the macrophage MAFB/MAF expression ratio might impair the exacerbated inflammatory and profibrotic responses, and restore the defective IFN type I production, thus becoming a potential strategy to limit severity of COVID-19.
Assuntos
COVID-19/imunologia , Macrófagos/imunologia , Fatores de Transcrição Maf/imunologia , Fator de Transcrição MafB/imunologia , SARS-CoV-2/imunologia , COVID-19/genética , COVID-19/virologia , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Macrófagos/metabolismo , Fatores de Transcrição Maf/genética , Fatores de Transcrição Maf/metabolismo , Fator de Transcrição MafB/genética , Fator de Transcrição MafB/metabolismo , SARS-CoV-2/fisiologia , Índice de Gravidade de DoençaRESUMO
Upon inflammation, monocyte-derived macrophages (MΦ) infiltrate blood vessels to regulate several processes involved in vascular pathophysiology. However, little is known about the mediators involved. Macrophage polarization is crucial for a fast and efficient initial response (GM-MΦ) and a good resolution (M-MΦ) of the inflammatory process. The functional activity of polarized MΦ is exerted mainly through their secretome, which can target other cell types, including endothelial cells. Endoglin (CD105) is a cell surface receptor expressed by endothelial cells and MΦ that is markedly upregulated in inflammation and critically involved in angiogenesis. In addition, a soluble form of endoglin with anti-angiogenic activity has been described in inflammation-associated pathologies. The aim of this work was to identify components of the MΦ secretome involved in the shedding of soluble endoglin. We find that the GM-MΦ secretome contains metalloprotease 12 (MMP-12), a GM-MΦ specific marker that may account for the anti-angiogenic activity of the GM-MΦ secretome. Cell surface endoglin is present in both GM-MΦ and M-MΦ, but soluble endoglin is only detected in GM-MΦ culture supernatants. Moreover, MMP-12 is responsible for the shedding of soluble endoglin in vitro and in vivo by targeting membrane-bound endoglin in both MΦ and endothelial cells. These data demonstrate a direct correlation between GM-MΦ polarization, MMP-12, and soluble endoglin expression and function. By targeting endothelial cells, MMP-12 may represent a novel mediator involved in vascular homeostasis.
Assuntos
Endoglina/metabolismo , Células Endoteliais/metabolismo , Mediadores da Inflamação/metabolismo , Macrófagos/metabolismo , Metaloproteinase 12 da Matriz/metabolismo , Animais , Células Cultivadas , Modelos Animais de Doenças , Suscetibilidade a Doenças , Endoglina/genética , Expressão Gênica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Inflamação/etiologia , Inflamação/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Macrófagos/imunologia , Camundongos , Modelos BiológicosRESUMO
El presente trabajo de investigación tiene como finalidad proponer el manejo adecuado de sustancias peligrosas en los laboratorios del Departamento de Biología de la Facultad de Ciencia y Tecnología de la Universidad de Carabobo, de acuerdo a la norma ambiental vigente. El tipo de investigación que se implementó fue documental y de campo. El tiempo de recolección de datos fue de cuatro meses y las herramientas utilizadas para la recolección de los mismos fueron la entrevista, la aplicación de encuesta y el muestreo; se trabajó con una muestra de 54 estudiantes y un técnico y un profesor para cada laboratorio. Se caracterizaron los efluentes una vez tomadas las muestras y también luego de la aplicación de los tratamientos fisicoquímicos (oxidación química para remover la DBO y la DQO) según el parámetro en estudio. Luego de la recolección de datos y el análisis de los resultados se determinó que los laboratorios no están tomando en cuenta un plan de manejo de las sustancias peligrosas que se deben manipular de acuerdo a lo establecido por la normativa legal vigente (Decreto 2635) y que algunos de los efluentes no cumple con los límites máximos permisibles para las descarga a redes cloacales según el Decreto 883. Finalmente se propone mejorar el plan de manejo de sustancias peligrosas mediante el acondicionamiento del depósito de desechos, la elaboración de hojas de seguridad y etiquetas para todos los reactivos, la señalización adecuada dentro de las instalaciones, la incineración de los desechos almacenados en el deposito destinado para ello y el reúso del formol y etanol.
The aim of this study was to propose ways to ensure the correct handling of hazardous substances in laboratories at the Department of Biology, Faculty of Science and Technology, Carabobo University. Both documentary and field data were collected. The survey was completed in four months and consisted of interviews, questionnaires and sampling. A total of 54 students, and one technician and one professor for each laboratory were surveyed. Samples were taken of all effluents and these were characterized before and after physiochemical treatments were implemented (chemical oxidation to remove BDO and CDO) when applicable. The laboratories surveyed did not follow pre-set procedures for the handling of hazardous substances, which should be manipulated according to the provisions of the current legislation (Decree No. 2635). In addition, the concentrations of some of the effluents were higher than the maximum permitted limits for discharge into the sewage system according to Decree No 883. The handling of hazardous substances could be greatly improved by: refurbishing the waste reservoir, drawing up safety data sheets, labelling chemical substances, the use of adequate signage within the facilities, incinerating waste materials stored in the designated warehouse and the reuse of formaldehyde and ethanol.
RESUMO
Some infectious pathogens have the capacity to affect cancer progression. In the present paper we studied the effect of infection or immunization with Trypanosoma cruzi (Tc) against malignant melanoma development. We worked on 258 C57BL/6 male mice divided in five melanoma groups: control melanoma, melanoma Tc acutely infected, melanoma Tc chronically infected, melanoma Tc immunized and infected melanoma; and three control groups: healthy, Tc acutely infected and Tc chronically infected. 100.000 B16-BL6 melanoma cells were inoculated in the thigh of melanoma groups; 3 or 20 trypomastigotes/g were inoculated intraperitoneally in chronic or acute Tc groups, before the melanoma injection, respectively; melanoma Tc immunized were subcutaneously inoculated with 30.000 formaldehide-fixed epimastigotes diluted in complete Freund's adjuvant and the infected melanoma group was inoculated with melanoma cells obtained from melanoma Tc acutely infected mice. We evaluated survival, parasitemia, tumor volume and tumor histopathology. Results showed that in mice infected with Tc, the tumor development and survival were significantly lower as compared with control melanoma and melanoma Tc immunized. Histopathologically, the tumor displayed necrosis areas with melanin deposits, cytopathic degeneration and amastigotes in parasitophorous vacuoles. In conclusion, Tc inhibits the development of malignant melanoma, increasing C57BL/6 survival, a phenomena that could be related to the parasite tumoral invasive capacity, its ability to produce melanoma cell lysis and to induce a robust immune response.
Assuntos
Doença de Chagas/imunologia , Melanoma/imunologia , Melanoma/mortalidade , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/mortalidade , Animais , Doença de Chagas/complicações , Masculino , Melanoma/complicações , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Cutâneas/complicações , Taxa de SobrevidaRESUMO
Diversos agentes infecciosos interfieren en la progresión del cáncer. En esta investigación se estudió el efecto de la infección o inmunización con Trypanosoma cruzi (Tc) sobre el desarrollo del melanoma maligno. Se utilizaron 258 ratones machos C57BL/6 divididos en 5 grupos melanoma: melanoma control, melanoma Tc inmunizado, melanoma Tc agudo, melanoma Tc crónico y melanoma Tc infectado; 3 grupos controles: control sano, control Tc agudo, control Tc crónico. 100.000 células de melanoma B16-BL6 fueron inoculados vía intramuscular a los grupos melanoma; 3 ó 20 tripomastigotes/g de peso fueron inoculados vía intraperitoneal a los grupos Tc crónicos o Tc agudos previo a la inoculación del melanoma, respectivamente, el grupo melanoma Tc inmunizado fue inoculado con 30.000 epimastigotes fijados en formol y suspendidos en adyuvante completo de Freund, y el grupo melanoma Tc infectado fue inoculado con células de melanoma obtenidas de ratones melanoma Tc agudo. Se evaluó volumen tumoral, supervivencia, parasitemia e histopatología tumoral. Los grupos melanoma Tc: agudo, crónico y melanoma infectado, respectivamente, mostraron una disminución significativa del desarrollo tumoral y de la supervivencia al ser comparados con los grupos melanoma control e inmunizado. Los estudios histopatológicos mostraron áreas de necrosis asociadas con depósitos de melanina, degeneración citopática tumoral y amastigotes intracelulares contenidos en vacuolas parasitofóricas. En conclusión, Tc inhibe el desarrollo tumoral del melanoma maligno y aumenta la supervivencia de ratones C57BL/6, fenómeno que podría estar relacionado con la capacidad invasiva tumoral del parásito y a la respuesta inmune generada.
Some infectious pathogens have the capacity to affect cancer progression. In the present paper we studied the effect of infection or immunization with Trypanosoma cruzi (Tc) against malignant melanoma development. We worked on 258 C57BL/6 male mice divided in five melanoma groups: control melanoma, melanoma Tc acutely infected, melanoma Tc chronically infected, melanoma Tc immunized and infected melanoma; and three control groups: healthy, Tc acutely infected and Tc chronically infected. 100.000 B16-BL6 melanoma cells were inoculated in the thigh of melanoma groups; 3 or 20 trypomastigotes/g were inoculated intraperitoneally in chronic or acute Tc groups, before the melanoma injection, respectively; melanoma Tc immunized were subcutaneously inoculated with 30.000 formaldehide-fixed epimastigotes diluted in complete Freund´s adjuvant and the infected melanoma group was inoculated with melanoma cells obtained from melanoma Tc acutely infected mice. We evaluated survival, parasitemia, tumor volume and tumor histopathology. Results showed that in mice infected with Tc, the tumor development and survival were significantly lower as compared with control melanoma and melanoma Tc immunized. Histopathologically, the tumor displayed necrosis areas with melanin deposits, cytopathic degeneration and amastigotes in parasitophorous vacuoles. In conclusion, Tc inhibits the development of malignant melanoma, increasing C57BL/6 survival, a phenomena that could be related to the parasite tumoral invasive capacity, its ability to produce melanoma cell lysis and to induce a robust immune response.
Assuntos
Animais , Masculino , Camundongos , Doença de Chagas/imunologia , Melanoma/imunologia , Melanoma/mortalidade , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/mortalidade , Doença de Chagas/complicações , Melanoma/complicações , Taxa de Sobrevida , Neoplasias Cutâneas/complicaçõesRESUMO
La presente revisión tuvo como propósito analizar las estrategias para el control de la contaminación debida a la formación de la corrosión e incrustaciones, basado en los factores que afectan el deterioro de los sistemas de distribución de agua potable, así como, su influencia sobre la calidad del agua suministrada al consumidor. Los sistemas de distribución pueden afectar la calidad del agua potable debido a las condiciones de la tubería y a la operación del sistema. La corrosión, las incrustaciones y los depósitos en la red de distribución, son otros de los problemas con mayor importancia en la industria del agua potable; esto puede afectar a la salud, la aceptación pública del suministro de agua y el costo de proveer un agua digna de confianza. Se concluye y se recomienda que como estrategias para controlar la corrosión y la formación de incrustaciones se deben seleccionar apropiadamente los materiales y el diseño del sistema, realizar el tratamiento químico adecuado (ajuste de pH, alcalinidad, oxigeno, uso de inhibidores de corrosión) y usar revestimientos y pinturas resistentes a la corrosión para proteger las paredes de las tuberías.
The aim of this review was to analyze control strategies of contamination caused by the formation of corrosion and incrustations based on factors affecting deterioration of distribution systems of potable water as well as its influence on the quality of water supplied to the consumer. Distribution systems can affect the quality of drinking water due to the conditions of the pipes and the systems operation. Corrosion, incrustations, and deposits in the distribution network major problems in the drinking water industry. These may affect health, public acceptance of the water supply and the cost of supplying reliable water. We conclude and recommend that, in order to control corrosion and the formation of incrustations, one must select appropriate materials and a sound system design, apply proper chemical treatment (adjusting pH, alkalinity, oxygen, the use of corrosion inhibitors) and use coatings and paints resistant to corrosion in order to protect the walls of the pipes.
Assuntos
Humanos , Poluição da Água/prevenção & controle , Qualidade da Água , Controle da Qualidade da Água , Purificação da Água , Água Potável , Saúde Pública , Purificação da Água , Abastecimento de ÁguaRESUMO
DC-SIGN (dendritic cell-specific ICAM-3-grabbing non-integrin) is a myeloid pathogen-attachment factor C-type lectin which recognizes mannose- and fucose-containing oligosaccharide ligands on clinically relevant pathogens. Intracellular signaling initiated upon ligand engagement of DC-SIGN interferes with TLR-initiated signals, and modulates the T cell activating and polarizing ability of antigen-presenting cells. The C-terminal carbohydrate-recognition domain (CRD) of DC-SIGN is preceded by a neck domain composed of eight 23-residue repeats which mediate molecule multimerization, and whose polymorphism correlates with altered susceptibility to SARS and HIV infection. Naturally occurring isoforms and chimaeric molecules, in combination with established recognition properties, were used to define seven structural and functional epitopes on DC-SIGN. Three epitopes mapped to the CRD, one of which is multimerization-dependent and only exposed on DC-SIGN monomers. Epitopes within the neck domain were conformation-independent and unaltered upon molecule multimerization, but were differentially affected by neck domain truncations. Although neck-specific antibodies exhibited lower function-blocking ability, they were more efficient at inducing molecule internalization. Moreover, crosslinking of the different epitopes resulted in distinct levels of microclustering on the cell surface. The identification of independent epitopes on the DC-SIGN molecule might facilitate the design of reagents that modulate the T cell activating and polarizing ability of DC-SIGN-expressing cells without preventing its antigen- and pathogen-recognition capacities.
Assuntos
Moléculas de Adesão Celular/química , Moléculas de Adesão Celular/imunologia , Mapeamento de Epitopos , Lectinas Tipo C/química , Lectinas Tipo C/imunologia , Receptores de Superfície Celular/química , Receptores de Superfície Celular/imunologia , Anticorpos Bloqueadores/imunologia , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos/imunologia , Linhagem Celular , Células Dendríticas/citologia , Células Dendríticas/imunologia , Endocitose/imunologia , Imunofluorescência , Humanos , Monócitos/citologia , Estrutura Terciária de ProteínaRESUMO
El objetivo principal de la investigación fue determinar la presencia de microorganismos patógenos (Pseudomonas aeruginosa y coliformes totales y fecales) así como los niveles de cloro residual y pH de ciertas piscinas ubicadas en tres municipios del estado Carabobo, a fin de proponer medidas de control según los hallazgos encontrados. Inicialmente se realizó un diagnóstico de las condiciones de las piscinas tomando en cuenta los siguientes aspectos: sistema de desinfección, sistema de filtración, normas de uso, sistema de renovación de agua y carga de bañistas (Gaceta Oficial de Venezuela Nº 4.044 Extraordinaria, 1988). Posteriormente se determinaron las características fisicoquímicas utilizando la norma COVENIN 2614:1994 y los Métodos Normalizados de Tratamiento de Agua y Agua Residual, y la evaluación bacteriológica por el método de Membrana Filtrante. De los resultados obtenidos se tiene que las piscinas clasificadas como aptas para el uso por parte de los bañistas corresponden a una del Municipio Valencia y una del Municipio Naguanagua. Así mismo, se clasificaron como no aptas siete piscinas del Municipio Valencia, tres del Municipio San Diego y una del Municipio de Naguanagua. Igualmente se evaluó como influyen los bañistas en el mantenimiento de las condiciones sanitarias de las piscinas, encontrándose que el uso de lociones u otras cremas en la piel como el factor más recurrente de contaminación. Finalmente, se propone un sistema de monitoreo periódico.
Assuntos
Coliformes , Pseudomonas aeruginosa , Saneamento de Piscinas , Piscinas , Microbiologia , VenezuelaRESUMO
La presente investigación tuvo como propósito un análisis de las estrategias para el control de la contaminación bacteriológica, basado en los factores que afectan el deterioro de los sistemas de distribución de agua potable, así como su influencia sobre la calidad del agua suministrada al consumidor. El sistema de distribución es de vital importancia para establecer la calidad final del agua, siendo las biopelículas que se forman en las paredes de las tuberías la causa de su deterioro. La agrupación de los diferentes microorganismos en colonias se considera como un mecanismo de defensa; estos se benefician de los nutrientes y se hacen fuertes frente a los desinfectantes. Se concluye y se recomienda que como estrategias para controlar la contaminación bacteriológica se debe establecer un programa de mantenimiento en todo el sistema e incluso en los tanques de almacenamiento. También es necesario el control de la corrosión y de los niveles de nutrientes y realizar practicas apropiadas de desinfección; estas medidas deben ser aplicadas por un personal capacitado, el cual debe mantenerse en constante entrenamiento.
Assuntos
Água Potável , Características Bacteriológicas da Água , Redes de Distribuição de Água , Poluição da Água , Saúde Ambiental , Saúde Pública , VenezuelaRESUMO
The P8 proteoglycolipid complex (P8 PGLC) is a glyconjugate expressed by Leishmania mexicana complex parasites. We previously have shown that vaccination with P8 PGLC provides protection against cutaneous leishmaniasis in susceptible BALB/c mice. However, the biological importance of this complex remains unknown. Here we show that P8 PGLC localizes to the surface of Leishmania pifanoi amastigotes and that upon exposure to macrophages, P8 PGLC binds and induces inflammatory cytokine and chemokine mRNAs such as tumor necrosis factor alpha and RANTES early after stimulation. Our studies indicate that cytokine and chemokine induction is dependent upon Toll-like receptor 4 (TLR4). Interestingly, key inflammatory cytokines and chemokines (such as interleukin-6 [IL-6], macrophage inflammatory protein 1beta, and beta interferon [IFN-beta]) that can be induced through TLR4 activation were not induced or only slightly upregulated by P8 PGLC. Activation by P8 PGLC does not occur in the presence of TLR4 alone and requires both CD14 and myeloid differentiation protein 2 for signaling; this requirement may be responsible for the limited TLR4 response. This is the first characterization of a TLR4 ligand for Leishmania. In vitro experiments indicate that L. pifanoi amastigotes induce lower levels of cytokines in macrophages in the absence of TLR4; however, notably higher IL-10/IFN-gamma ratios were found for TLR4-deficient mice than for BALB/c mice. Further, increased levels of parasites persist in BALB/c mice deficient in TLR4. Taken together, these results suggest that TLR4 recognition of Leishmania pifanoi amastigotes is important for the control of infection and that this is mediated, in part, through the P8 PGLC.
Assuntos
Citocinas/biossíntese , Leishmania/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/parasitologia , Proteolipídeos/imunologia , Receptor 4 Toll-Like/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Contagem de Células , Linhagem Celular , Células Cultivadas , Citocinas/genética , Feminino , Perfilação da Expressão Gênica , Humanos , Leishmania/química , Leishmaniose/imunologia , Leishmaniose/parasitologia , Receptores de Lipopolissacarídeos/imunologia , Antígeno 96 de Linfócito , Proteínas de Membrana/análise , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteolipídeos/análise , Proteolipídeos/isolamento & purificação , Receptor 4 Toll-Like/deficiênciaRESUMO
AM3 (Inmunoferon) is an orally effective immunomodulator that influences the regulatory and effector functions of the immune system whose molecular mechanisms of action are mostly unknown. We hypothesized that the polysaccharide moiety of AM3 (IF-S) might affect immune responses by modulating the lectin-dependent pathogen recognition abilities of human dendritic cells. IF-S inhibited binding of viral, fungal, and parasite pathogens by human monocyte-derived dendritic cells in a dose-dependent manner. IF-S specifically impaired the pathogen recognition capabilities of DC-SIGN, as it reduced the attachment of Candida, Aspergillus, and Leishmania to DC-SIGN transfectants. IF-S also inhibited the interaction of DC-SIGN with both its cellular counterreceptor (intercellular adhesion molecule 3) and the human immunodeficiency virus (HIV) type 1 gp120 protein and blocked the DC-SIGN-dependent capture of HIV virions and the HIV trans-infection capability of DC-SIGN transfectants. IF-S promoted DC-SIGN internalization in DCs without affecting mannose receptor expression, and (1)D saturation transfer difference nuclear magnetic resonance demonstrated that IF-S directly interacts with DC-SIGN on the cell surface. Therefore, the polysaccharide moiety of AM3 directly influences pathogen recognition by dendritic cells by interacting with DC-SIGN. Our results indicate that DC-SIGN is the target for an immunomodulator and imply that the adjuvant and immunomodulatory actions of AM3 are mediated, at least in part, by alteration of the DC-SIGN functional activities.
Assuntos
Adjuvantes Imunológicos/farmacologia , Fosfatos de Cálcio/farmacologia , Moléculas de Adesão Celular/metabolismo , Células Dendríticas/efeitos dos fármacos , Glicopeptídeos/farmacologia , Lectinas Tipo C/metabolismo , Receptores de Superfície Celular/metabolismo , Adjuvantes Imunológicos/química , Animais , Aspergillus fumigatus/efeitos dos fármacos , Fosfatos de Cálcio/química , Candida albicans/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fluoresceína-5-Isotiocianato , Técnica Indireta de Fluorescência para Anticorpo , Corantes Fluorescentes , Glicopeptídeos/química , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/patogenicidade , Humanos , Células K562 , Leishmania/efeitos dos fármacos , Leucócitos Mononucleares/citologia , Polissacarídeos/metabolismo , Ligação ProteicaRESUMO
Liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin [CLEC4G]) is a C-type lectin encoded within the liver/lymph node-specific intercellular adhesion molecule-3-grabbing nonintegrin (L-SIGN)/dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN)/CD23 gene cluster. LSECtin expression has been previously described as restricted to sinusoidal endothelial cells of the liver and lymph node. We now report LSECtin expression in human peripheral blood and thymic dendritic cells isolated ex vivo. LSECtin is also detected in monocyte-derived macrophages and dendritic cells at the RNA and protein level. In vitro, interleukin-4 (IL-4) induces the expression of 3 LSECtin alternatively spliced isoforms, including a potentially soluble form (Delta 2 isoform) and a shorter version of the prototypic molecule (Delta3/4 isoform). LSECtin functions as a pathogen receptor, because its expression confers Ebola virus-binding capacity to leukemic cells. Sugar-binding studies indicate that LSECtin specifically recognizes N-acetyl-glucosamine, whereas no LSECtin binding to Mannan- or N-acetyl-galactosamine-containing matrices are observed. Antibody or ligand-mediated engagement triggers a rapid internalization of LSECtin,which is dependent on tyrosine and diglutamic-containing motifs within the cytoplasmic tail. Therefore, LSECtin is a pathogen-associated molecular pattern receptor in human myeloid cells. In addition, our results suggest that LSECtin participates in antigen uptake and internalization, and might be a suitable target molecule in vaccination strategies.
Assuntos
Antígenos/imunologia , Lectinas Tipo C/imunologia , Células Mieloides/imunologia , Patógenos Transmitidos pelo Sangue , Células Dendríticas/imunologia , Endocitose , Humanos , Lectinas Tipo C/análise , Lectinas Tipo C/genética , Macrófagos/imunologia , Isoformas de Proteínas , RNA Mensageiro/análiseRESUMO
PURPOSE: Cytokines and other growth factors such as interleukins play an important role in the pathogenesis of proliferative vitreoretinopathy (PVR). Interindividual variations in cytokine production seem to correlate with some cytokine gene polymorphisms. The purpose of this study was to analyse the distribution of these cytokine gene variants in patients with rhegmatogenous retinal detachment (RD) with and without PVR. METHODS: Single nucleotide polymorphisms were analysed for five cytokines: tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta1 (TGF-beta1), interferon-gamma (IFN-gamma), interleukin-6 (IL-6) and interleukin-10 (IL-10). Patients were divided into two surgically treated groups of RD patients: group RD had 27 patients with RD, and group PVR had 31 patients with RD complicated by PVR. A control group was composed of 46 ethnically matched healthy individuals. RESULTS: The genotype distribution of the TGF-beta1 codon 10 polymorphism differed between PVR and RD patients (p = 0.018) and between PVR patients and controls in codon 25 (p = 0.011). There was a higher frequency of TGF-beta1 codon 10 allele T in PVR patients compared with RD patients (p = 0.023). No statistically significant differences between groups were observed for the other polymorphisms examined. CONCLUSION: An association between the TGF-beta1 genetic profile and the development of PVR was detected in this study. Further studies are necessary to confirm this finding and to establish its clinical relevance.
Assuntos
Citocinas/genética , Marcadores Genéticos , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único , Descolamento Retiniano/genética , Vitreorretinopatia Proliferativa/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA/genética , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Descolamento Retiniano/complicações , Fatores de Risco , Vitreorretinopatia Proliferativa/complicaçõesRESUMO
Dendritic cells (DC) play an important role in innate and adaptive immunity, interacting with T cells, NK, and NKT cells. A critical step in the interaction of the parasitic protozoa Leishmania with their host is the evasion of both innate and adaptive immunity, producing a long-lasting chronic infection. There is growing evidence that these parasites can modify the Ag-presenting and immunoregulatory functions of DCs. The cells and mechanisms involved in innate immune response against Leishmania are still poorly understood. In this study, we investigated how Leishmania infantum infection affects DC interactions with NK and invariant NKT (iNKTs) cells in humans. We found that infected immature DCs (iDCs) do not up-regulate HLA class I molecules. Despite this, iDCs become resistant to killing mediated by autologous NK cells due to the up-regulation of HLA-E expression, which protects target cells from NK-mediated lysis through interaction with the inhibitory receptor CD94/NKG2A. Furthermore, iDCs infected with L. infantum up-regulate CD1d cell surface expression and consequently can be efficiently recognized and killed by iNKT cells that produce IFN-gamma. These data suggest that L. infantum could be able to evade NK recognition; in contrast, iNKTs may play an important role in the immune response against Leishmania.
Assuntos
Apresentação de Antígeno/imunologia , Diferenciação Celular/imunologia , Citotoxicidade Imunológica , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Células Matadoras Naturais/imunologia , Leishmania infantum/imunologia , Linfócitos T/imunologia , Animais , Células Cultivadas , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Humanos , Imunidade Inata , Células Matadoras Naturais/metabolismo , Linfócitos T/metabolismoRESUMO
Leishmaniasis is a parasitic disease that courses with cutaneous or visceral clinical manifestations. The amastigote stage of the parasite infects phagocytes and modulates the effector function of the host cells. Our group has described that the interaction between Leishmania and immature monocyte-derived dendritic cells (DCs) takes place through dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), a C-type lectin that specifically recognizes fungal, viral and bacterial pathogens. The DC-SIGN-mediated recognition of Leishmania amastigotes does not induce DC maturation, and the DC-SIGN ligand/s on Leishmania parasites is/are still unknown. We have also found that the DC-SIGN-related molecule L-SIGN, specifically expressed in lymph node and liver sinusoidal endothelial cells, acts as a receptor for L. infantum, the parasite responsible for visceral leishmaniasis, but does not recognize L. pifanoi, which causes the cutaneous form of the disease. Therefore, DC-SIGN and L-SIGN differ in their ability to interact with Leishmania species responsible for either visceral or cutaneous leishmaniasis. A deeper knowledge of the parasite-C-type lectin interaction may be helpful for the design of new DC-based therapeutic vaccines against Leishmania infections.
Assuntos
Moléculas de Adesão Celular/imunologia , Lectinas Tipo C/imunologia , Leishmania/imunologia , Leishmaniose/imunologia , Fagócitos/parasitologia , Receptores de Superfície Celular/imunologia , Animais , Moléculas de Adesão Celular/metabolismo , Humanos , Lectinas Tipo C/metabolismo , Leishmania/metabolismo , Leishmaniose/metabolismo , Receptores de Superfície Celular/metabolismoRESUMO
Dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN) is a type II C-type lectin that functions as an adhesion receptor and mediates binding and internalization of pathogens such as virus (human immunodeficiency virus, hepatitis C), bacteria (Mycobacterium), fungi, and parasites. DC-SIGN expression in vivo is primarily restricted to interstitial dendritic cells (DC) and certain tissue macrophages. We now report that leukemic THP-1 cells, widely used as a model for monocyte-macrophage differentiation, express very low basal levels of DC-SIGN and that DC-SIGN expression in THP-1 cells is regulated during differentiation. Differentiation-inducing agents (phorbol ester, bryostatin) conveyed THP-1 cells with the ability to up-regulate DC-SIGN mRNA levels and cell surface expression in response to interleukin-4 (IL-4) or IL-13. DC-SIGN up-regulation required a functional JAK-STAT signaling pathway, was inhibited in the presence of lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha), and conferred THP-1 cells with increased pathogen recognition and T cell stimulatory capabilities. The up-regulation of DC-SIGN on THP-1 cells resembles its inducible expression on monocytes and macrophages, where DC-SIGN expression is also induced by IL-4/IL-13 and negatively regulated by TNF-alpha, LPS, and vitamin D(3). These results point to THP-1 cells as a useful cellular system to characterize the pathogen-binding capabilities of DC-SIGN and to dissect the molecular mechanisms that control its regulated and tissue-specific expression in myeloid dendritic cells, and the results suggest that DC-SIGN constitutes a marker for both DC and alternatively activated macrophages.