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1.
Elife ; 102021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34212857

RESUMO

Mannose-sensitive hemagglutinin (MSHA) pili and flagellum are critical for the surface attachment of Vibrio cholerae, the first step of V. cholerae colonization on host surfaces. However, the cell landing mechanism remains largely unknown, particularly in viscoelastic environments such as the mucus layers of intestines. Here, combining the cysteine-substitution-based labeling method with single-cell tracking techniques, we quantitatively characterized the landing of V. cholerae by directly observing both pili and flagellum of cells in a viscoelastic non-Newtonian solution consisting of 2% Luria-Bertani and 1% methylcellulose (LB+MC). The results show that MSHA pili are evenly distributed along the cell length and can stick to surfaces at any point along the filament. With such properties, MSHA pili are observed to act as a brake and anchor during cell landing which includes three phases: running, lingering, and attaching. Importantly, loss of MSHA pili results in a more dramatic increase in mean path length in LB+MC than in 2% LB only or in 20% Ficoll solutions, indicating that the role of MSHA pili during cell landing is more apparent in viscoelastic non-Newtonian fluids than viscous Newtonian ones. Our work provides a detailed picture of the landing dynamics of V. cholerae under viscoelastic conditions, which can provide insights into ways to better control V. cholerae infections in a real mucus-like environment.


Assuntos
Proteínas de Fímbrias/fisiologia , Flagelos/fisiologia , Vibrio cholerae/fisiologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Lectina de Ligação a Manose/fisiologia , Movimento , Análise de Célula Única , Substâncias Viscoelásticas
2.
Kidney Int ; 98(2): 314-322, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32461141

RESUMO

The novel coronavirus disease COVID-19 originates in the lungs, but it may extend to other organs, causing, in severe cases, multiorgan damage, including cardiac injury and acute kidney injury. In severe cases, the presence of kidney injury is associated with increased risk of death, highlighting the relevance of this organ as a target of SARS-CoV-2 infection. COVID-19-associated tissue injury is not primarily mediated by viral infection, but rather is a result of the inflammatory host immune response, which drives hypercytokinemia and aggressive inflammation that affect lung parenchymal cells, diminishing oxygen uptake, but also endothelial cells, resulting in endotheliitis and thrombotic events and intravascular coagulation. The complement system represents the first response of the host immune system to SARS-CoV-2 infection, but there is growing evidence that unrestrained activation of complement induced by the virus in the lungs and other organs plays a major role in acute and chronic inflammation, endothelial cell dysfunction, thrombus formation, and intravascular coagulation, and ultimately contributes to multiple organ failure and death. In this review, we discuss the relative role of the different complement activation products in the pathogenesis of COVID-19-associated tissue inflammation and thrombosis and propose the hypothesis that blockade of the terminal complement pathway may represent a potential therapeutic option for the prevention and treatment of lung and multiorgan damage.


Assuntos
Betacoronavirus , Ativação do Complemento , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Animais , COVID-19 , Complemento C5a/fisiologia , Infecções por Coronavirus/complicações , Células Endoteliais/fisiologia , Humanos , Inflamação/etiologia , Lectina de Ligação a Manose/fisiologia , Camundongos , Pandemias , Pneumonia Viral/complicações , SARS-CoV-2 , Trombose/etiologia , Doenças Vasculares/etiologia
3.
J Zhejiang Univ Sci B ; 21(3): 192-203, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32133797

RESUMO

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.


Assuntos
Nefropatias Diabéticas/etiologia , Receptores de Reconhecimento de Padrão/fisiologia , Alarminas/fisiologia , Proteína C-Reativa/análise , Proteína C-Reativa/fisiologia , Endocitose , Humanos , Imunidade Inata , Lectina de Ligação a Manose/fisiologia , Moléculas com Motivos Associados a Patógenos , Componente Amiloide P Sérico/fisiologia , Transdução de Sinais
4.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-1010527

RESUMO

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.


Assuntos
Humanos , Alarminas/fisiologia , Proteína C-Reativa/fisiologia , Nefropatias Diabéticas/etiologia , Endocitose , Imunidade Inata , Lectina de Ligação a Manose/fisiologia , Moléculas com Motivos Associados a Patógenos , Receptores de Reconhecimento de Padrão/fisiologia , Componente Amiloide P Sérico/fisiologia , Transdução de Sinais
5.
Exp Dermatol ; 28(9): 1017-1024, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31260126

RESUMO

Psoriasis is a chronic, relapsing inflammatory skin disorder. Numerous experimental evidence and therapeutic evidence have shown that the innate immune response is critical for the pathogenesis and development of psoriasis. Mannan-binding lectin (MBL), a prototypic pattern recognition molecule of the innate immune system, plays an essential role in the host defense against certain infections and also appears to be a major regulator of inflammation. In this study, we investigated the function of MBL on the course of experimental murine imiquimod (IMQ)-induced psoriasis. Our data showed that MBL-deficient (MBL-/- ) mice exhibited attenuated skin damage characterized by greatly decreased erythema compared with wild-type control mice during the early stages of IMQ-induced psoriasis-like skin inflammation. The reduced skin inflammation in MBL-/- mice was associated with the decreased infiltration of neutrophils. Furthermore, we have determined that MBL deficiency limited the chemokine CXCL1 production from skin keratinocytes upon IMQ stimulation, which might be responsible for the impaired skin recruitment of neutrophils. Additionally, we have provided the data that MBL protein promotes the IMQ-induced expression of CXCL1 and activation of MAPK/NF-κB signalling pathway in human keratinocyte HaCaT cells in vitro. In summary, our study revealed an unexpected role of MBL on keratinocyte function in skin, thus offering a new insight into the pathogenic mechanisms of psoriasis.


Assuntos
Quimiocina CXCL1/biossíntese , Quimiotaxia de Leucócito , Queratinócitos/metabolismo , Lectina de Ligação a Manose/fisiologia , Neutrófilos/fisiologia , Psoríase/imunologia , Animais , Linhagem Celular Transformada , Quimiocina CXCL1/genética , Derme/imunologia , Derme/patologia , Feminino , Humanos , Imiquimode/toxicidade , Inflamação , Queratinócitos/efeitos dos fármacos , Lectina de Ligação a Manose/deficiência , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Lectina de Ligação a Manose/farmacologia , Erros Inatos do Metabolismo/complicações , Erros Inatos do Metabolismo/imunologia , Camundongos , Camundongos Knockout , Psoríase/induzido quimicamente , Psoríase/metabolismo , Organismos Livres de Patógenos Específicos , Regulação para Cima
6.
Dis Aquat Organ ; 124(2): 159-163, 2017 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-28425428

RESUMO

The channel catfish virus (CCV) is a pathogenic herpesvirus that infects channel catfish Ictalurus punctatus in pond aquaculture in the southeastern USA. Mannose-binding lectin (MBL), an innate immune protein, could play an important role in the innate response of channel catfish by binding to CCV. Cell cultures of CCV were grown in channel catfish ovary cells (CCOC). A dot-immunoblot enzyme-linked immunosorbent assay was done to determine the binding ability of 5 mo old channel catfish serum MBL (26.2 µg ml-1) to CCOC infected with CCV. Two separate nitrocellulose membrane blotting techniques were done using uninfected and infected CCOC. The uninfected CCOC decreased by 29.3 and 33.4% in their binding of channel catfish MBL when compared with infected CCOC using the 2 membrane procedures. The combined average binding ability of channel catfish MBL towards infected CCOC was therefore 31.4% greater when comparing the infected and uninfected CCOC. Normalization equation values of MBL for the 5 mo old catfish were compared for the 2 membrane binding procedures. The 2 normalization values were very close (142 and 150) in binding ability of MBL to the infected CCOC. The 5 mo catfish serum had twice the concentration of MBL (26.2 µg ml-1) compared to 7 mo catfish serum (13.2 µg ml-1), and the binding percentage of 5 mo serum was 2.4 times greater in infected than in uninfected cells. This demonstrates that the binding of channel catfish serum MBL to CCV is concentration dependent and is related to serum concentrations of MBL.


Assuntos
Infecções por Herpesviridae/veterinária , Ictaluridae/sangue , Ictalurivirus/imunologia , Imunidade Inata/fisiologia , Lectina de Ligação a Manose/fisiologia , Animais , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Infecções por Herpesviridae/virologia , Immunoblotting , Lectina de Ligação a Manose/sangue , Ovário/citologia , Ligação Proteica
7.
J Immunol Res ; 2017: 7045630, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28246614

RESUMO

The mannose-binding lectin (MBL) is a member of the collectin family, belonging to the innate immunity system. Genetic, biologic, and clinical properties of MBL have been widely investigated throughout the last decades, although some interesting aspects of its potential clinical relevance are still poorly understood. Low circulating concentrations of MBL have been associated with increased risk of infection and poor neurologic outcome in neonates. On the other hand, an excessive and uncontrolled inflammatory response by the neonatal intestine after the exposure to luminal bacteria, leading to an increased production of MBL, may be involved in the onset of necrotizing enterocolitis. The purpose of the present review is to summarize the current knowledge about genetic and biologic characteristics of MBL and its role in the susceptibility to infections and to ischemia-reperfusion related tissue injuries to better explore its clinical relevance during the perinatal period and the possible future therapeutic applications.


Assuntos
Suscetibilidade a Doenças , Lectina de Ligação a Manose/sangue , Lectina de Ligação a Manose/fisiologia , Traumatismo por Reperfusão/etiologia , Estado Terminal , Enterocolite Necrosante/imunologia , Enterocolite Necrosante/microbiologia , Humanos , Imunidade Inata , Recém-Nascido , Recém-Nascido Prematuro , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/uso terapêutico , Polimorfismo Genético , Traumatismo por Reperfusão/imunologia
8.
Sci Rep ; 6: 37339, 2016 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-27853317

RESUMO

To characterize the interaction potential of the human vaginal isolate Lactobacillus plantarum CMPG5300, its genome was mined for genes encoding lectin-like proteins. cmpg5300.05_29 was identified as the gene encoding a putative mannose-binding lectin. Phenotypic analysis of a gene knock-out mutant of cmpg5300.05_29 showed that expression of this gene is important for auto-aggregation, adhesion to the vaginal epithelial cells, biofilm formation and binding to mannosylated glycans. Purification of the predicted lectin domain of Cmpg5300.05_29 and characterization of its sugar binding capacity confirmed the specificity of the lectin for high- mannose glycans. Therefore, we renamed Cmpg5300.05_29 as a mannose-specific lectin (Msl). The purified lectin domain of Msl could efficiently bind to HIV-1 glycoprotein gp120 and Candida albicans, and showed an inhibitory activity against biofilm formation of uropathogenic Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Thus, using a combination of molecular lectin characterization and functional assays, we could show that lectin-sugar interactions play a key role in host and pathogen interactions of a prototype isolate of the vaginal Lactobacillus microbiota.


Assuntos
Proteínas de Bactérias/fisiologia , Lactobacillus plantarum/fisiologia , Lectina de Ligação a Manose/fisiologia , Vagina/microbiologia , Aglutinação , Aderência Bacteriana , Proteínas de Bactérias/farmacologia , Biofilmes , Candida albicans/fisiologia , Configuração de Carboidratos , Sequência de Carboidratos , Células Epiteliais/microbiologia , Feminino , Proteína gp120 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/química , HIV-1/fisiologia , Humanos , Mananas/química , Lectina de Ligação a Manose/farmacologia , Interações Microbianas , Ligação Proteica , Saccharomyces cerevisiae/fisiologia , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/fisiologia
9.
Arq Bras Cir Dig ; 29(1): 57-9, 2016 Mar.
Artigo em Inglês, Português | MEDLINE | ID: mdl-27120743

RESUMO

Mannose binding lectin is a lectin instrumental in the innate immunity. It recognizes carbohydrate patterns found on the surface of a large number of pathogenic micro-organisms, activating the complement system. However, this protein seems to increase the tissue damage after ischemia. In this paper is reviewed some aspects of harmful role of the mannose binding lectin in ischemia/reperfusion injury.


Assuntos
Reestenose Coronária/etiologia , Lectina de Ligação a Manose/fisiologia , Traumatismo por Reperfusão/etiologia , Constrição Patológica/etiologia , Estenose Coronária/etiologia , Humanos
10.
Am J Physiol Lung Cell Mol Physiol ; 311(2): L280-91, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27106289

RESUMO

Ozone is a common, potent oxidant pollutant in industrialized nations. Ozone exposure causes airway hyperreactivity, lung hyperpermeability, inflammation, and cell damage in humans and laboratory animals, and exposure to ozone has been associated with exacerbation of asthma, altered lung function, and mortality. The mechanisms of ozone-induced lung injury and differential susceptibility are not fully understood. Ozone-induced lung inflammation is mediated, in part, by the innate immune system. We hypothesized that mannose-binding lectin (MBL), an innate immunity serum protein, contributes to the proinflammatory events caused by ozone-mediated activation of the innate immune system. Wild-type (Mbl(+/+)) and MBL-deficient (Mbl(-/-)) mice were exposed to ozone (0.3 ppm) for up to 72 h, and bronchoalveolar lavage fluid was examined for inflammatory markers. Mean numbers of eosinophils and neutrophils and levels of the neutrophil attractants C-X-C motif chemokines 2 [Cxcl2 (major intrinsic protein 2)] and 5 [Cxcl5 (limb expression, LIX)] in the bronchoalveolar lavage fluid were significantly lower in Mbl(-/-) than Mbl(+/+) mice exposed to ozone. Using genome-wide mRNA microarray analyses, we identified significant differences in transcript response profiles and networks at baseline [e.g., nuclear factor erythroid-related factor 2 (NRF2)-mediated oxidative stress response] and after exposure (e.g., humoral immune response) between Mbl(+/+) and Mbl(-/-) mice. The microarray data were further analyzed to discover several informative differential response patterns and subsequent gene sets, including the antimicrobial response and the inflammatory response. We also used the lists of gene transcripts to search the LINCS L1000CDS(2) data sets to identify agents that are predicted to perturb ozone-induced changes in gene transcripts and inflammation. These novel findings demonstrate that targeted deletion of Mbl caused differential levels of inflammation-related gene sets at baseline and after exposure to ozone and significantly reduced pulmonary inflammation, thus indicating an important innate immunomodulatory role of the gene in this model.


Assuntos
Poluentes Atmosféricos/toxicidade , Imunidade Inata , Lectina de Ligação a Manose/fisiologia , Ozônio/toxicidade , Pneumonia/imunologia , Animais , Ontologia Genética , Pulmão/imunologia , Pulmão/metabolismo , Masculino , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pneumonia/metabolismo , Mapas de Interação de Proteínas , Transcriptoma
11.
Cell Microbiol ; 18(10): 1459-70, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26990156

RESUMO

Predation by phagocytic predators is a major source of bacterial mortality. The first steps in protozoan predation are recognition and consumption of their bacterial prey. However, the precise mechanisms governing prey recognition and phagocytosis by protists, and the identities of the molecular and cellular factors involved in these processes are, as yet, ill-characterized. Here, we show that that the ability of the phagocytic bacterivorous amoebae, Acanthamoeba castellanii, to recognize and internalize Escherichia coli, a bacterial prey, varies with LPS structure and composition. The presence of an O-antigen carbohydrate is not required for uptake of E. coli by A. castellanii. However, O1-antigen types, not O157 O-antigen types, inhibit recognition and uptake of bacteria by amoeba. This finding implies that O-antigen may function as an antipredator defence molecule. Recognition and uptake of E. coli by A. castellanii is mediated by the interaction of mannose-binding protein located on amoebae's surface with LPS carbohydrate. Phagocytic mammalian cells also use mannose-binding lectins to recognize and/or mediate phagocytosis of E. coli. Nonetheless, A. castellanii's mannose binding protein apparently displays no sequence similarity with any known metazoan mannose binding protein. Hence, the similarity in bacterial recognition mechanisms of amoebae and mammalian phagocytes may be a result of convergent evolution.


Assuntos
Acanthamoeba castellanii/microbiologia , Escherichia coli O157/fisiologia , Acanthamoeba castellanii/imunologia , Acanthamoeba castellanii/metabolismo , Células Cultivadas , Interações Hospedeiro-Patógeno , Lipopolissacarídeos/farmacologia , Lectina de Ligação a Manose/fisiologia
12.
ABCD (São Paulo, Impr.) ; 29(1): 57-59, Jan.-Mar. 2016. graf
Artigo em Inglês | LILACS | ID: lil-780017

RESUMO

Mannose binding lectin is a lectin instrumental in the innate immunity. It recognizes carbohydrate patterns found on the surface of a large number of pathogenic micro-organisms, activating the complement system. However, this protein seems to increase the tissue damage after ischemia. In this paper is reviewed some aspects of harmful role of the mannose binding lectin in ischemia/reperfusion injury.


Lectina de ligação à manose é uma lectina instrumental na imunidade inata. Ela reconhece padrões de hidratos de carbono encontrados na superfície de um grande número de microrganismos patogênicos, que ativam o sistema complemento. No entanto, esta proteína parece aumentar o dano tecidual após isquemia. Neste trabalho são revisados alguns aspectos do papel nocivo da lectina de ligação à manose na lesão de isquemia/reperfusão.


Assuntos
Humanos , Traumatismo por Reperfusão/etiologia , Reestenose Coronária/etiologia , Lectina de Ligação a Manose/fisiologia , Constrição Patológica/etiologia , Estenose Coronária/etiologia
13.
Chemistry ; 22(11): 3686-91, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26696414

RESUMO

Antagonists of mannose binding lectin (MBL) have shown a protective role against brain reperfusion damage after acute ischemic stroke. Here we describe the design and streamlined synthesis of glycomimetic MBL antagonists based on a new tetravalent dendron scaffold. The dendron was developed by optimisation of a known polyester structure previously demonstrated to be very efficient for ligand presentation to MBL. Replacement of a labile succinyl ester bond with a more robust amide functionality, use of a longer and more hydrophilic linker, fast modular synthesis and orthogonal functionalisation at the focal point are the main features of the new scaffold. The glycoconjugate constructs become stable to silica gel chromatography and to water solutions at physiological pH, while preserving water solubility and activity in an SPR assay against the murine MBL-C isoform. Higher-order constructs were easily assembled, as demonstrated by the synthesis of a 16-valent dendrimer, which leads to two orders of magnitude increase in activity over the tetravalent version against MBL-C.


Assuntos
Isquemia Encefálica/fisiopatologia , Dendrímeros/química , Glicoconjugados/química , Lectina de Ligação a Manose/deficiência , Acidente Vascular Cerebral/patologia , Animais , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Glicoconjugados/metabolismo , Ligantes , Lectina de Ligação a Manose/fisiologia , Camundongos
14.
Mol Neurobiol ; 52(3): 1330-1340, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25341475

RESUMO

The activation of the complement system may be involved in the pathology of stroke and type 2 diabetes (T2DM). We therefore evaluated the long-term prognostic value of early measurement of serum mannose-binding lectin (MBL) levels, an activator of the complement system, in Chinese T2DM with acute ischemic stroke (AIS). Serum MBL levels were determined in T2DM patients with AIS (N = 188). The adjudicated end points were 1-year functional outcomes and mortality. The prognostic value of MBL was compared with the National Institutes of Health Stroke Scale score and with other known outcome predictors. Patients with an unfavorable outcomes and nonsurvivors had significantly increased MBL levels on admission (P < 0.0001 and P < 0.0001). Multivariate logistic regression analysis adjusted for common risk factors showed that MBL was an independent predictor of functional outcome (odds ratio (OR) = 8.99, 95% CI 2.21-30.12) and mortality (OR = 13.22, 95% CI 2.05-41.21). The area under the receiver operating characteristic curve of MBL was 0.75 (95% CI 0.68-0.83) for functional outcome and 0.85 (95% CI 0.80-0.90) for mortality. In type 2 diabetic patients with stroke, high levels of MBL predict future functional outcomes and mortality. This indicated that the elevated MBL levels may play a significant role in the pathology of the subsequent damage and that the pathways leading to complement activation warrant further exploration as potential therapeutic targets to improve the prognosis for these patients.


Assuntos
Isquemia Encefálica/sangue , Diabetes Mellitus Tipo 2/sangue , Lectina de Ligação a Manose/sangue , Idoso , Área Sob a Curva , Biomarcadores , Dano Encefálico Crônico/epidemiologia , Dano Encefálico Crônico/etiologia , Isquemia Encefálica/complicações , Isquemia Encefálica/imunologia , Isquemia Encefálica/mortalidade , China/epidemiologia , Comorbidade , Ativação do Complemento , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/imunologia , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Masculino , Lectina de Ligação a Manose/fisiologia , Pessoa de Meia-Idade , Neuroimagem , Prognóstico , Estudos Prospectivos , Curva ROC , Fatores de Risco
15.
Vet Immunol Immunopathol ; 163(1-2): 23-32, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25487759

RESUMO

Mannose-binding lectin (MBL) is a key protein in innate immunity. MBL binds to carbohydrates on the surface of pathogens, where it initiates complement activation via the lectin-dependent pathway or facilitates opsonophagocytosis. In vitro studies have shown that human MBL is able to bind to Salmonella, but knowledge in relation to chicken MBL and Salmonella is lacking. In order to study this relation day-old chickens from two selected lines L10H and L10L, differing in MBL serum concentration, were either orally infected with S. Infantis (S.123443) or kept as non-infected controls. The differences between healthy L10H and L10L chicken sublines were more profound than differences caused by the S. Infantis infection. The average daily body weight was higher for L10H than for L10L, regardless of infection, indicating beneficial effects of MBL selection on growth. Salmonella was detected in cloacal swabs and the number of Salmonella positive chickens during the experiment was significantly higher in L10L than L10H, indicating that MBL may affect the magnitude of Salmonella colonisation in day-old chickens. MBL expression was determined in ceca tissue by real-time RT-PCR. L10H chickens showed a significantly higher relative expression than L10L at days 1 and 41 pi, regardless of infection. Finally, flow cytometric analysis of whole blood from infected chickens showed that L10H had a significantly higher count of all assessed leucocyte subsets on day 5 pi, and also a higher count of monocytes on day 12 pi than L10L. No difference was observed between infected and non-infected L10L chicken.


Assuntos
Lectina de Ligação a Manose/deficiência , Doenças das Aves Domésticas/imunologia , Salmonelose Animal/imunologia , Animais , Galinhas/sangue , Galinhas/genética , Galinhas/imunologia , Suscetibilidade a Doenças/imunologia , Suscetibilidade a Doenças/veterinária , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Citometria de Fluxo/veterinária , Genótipo , Imunidade Inata/imunologia , Contagem de Leucócitos/veterinária , Complexo Principal de Histocompatibilidade/genética , Masculino , Lectina de Ligação a Manose/sangue , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/fisiologia , Doenças das Aves Domésticas/etiologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Salmonelose Animal/etiologia , Salmonella enterica/imunologia
16.
Stroke ; 45(5): 1453-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24676774

RESUMO

BACKGROUND AND PURPOSE: Several lines of evidence support the involvement of mannose-binding lectin (MBL) in stroke brain damage. The lectin pathway of the complement system facilitates thrombin activation and clot formation under certain experimental conditions. In the present study, we examine whether MBL promotes thrombosis after ischemia/reperfusion and influences the course and prognosis of ischemic stroke. METHODS: Middle cerebral artery occlusion/reperfusion was performed in MBL-deficient (n=85) and wild-type (WT; n=83) mice, and the brain lesion was assessed by MRI at days 1 and 7. Relative cerebral blood flow was monitored up to 6 hours after middle cerebral artery occlusion with laser speckle contrast imaging. Fibrin(ogen) was analyzed in the brain vasculature and plasma, and the effects of thrombin inhibitor argatroban were evaluated to assess the role of MBL in thrombin activation. RESULTS: Infarct volumes and neurological deficits were smaller in MBL knockout mice than in WT mice. Relative cerebral blood flow values during middle cerebral artery occlusion and at reperfusion were similar in both groups, but decreased during the next 6 hours in the WT group only. Also, the WT mice showed more fibrin(ogen) in brain vessels and a better outcome after argatroban treatment. In contrast, argatroban did not improve the outcome in MBL knockout mice. CONCLUSIONS: MBL promotes brain damage and functional impairment after brain ischemia/reperfusion in mice. These effects are secondary to intravascular thrombosis and impaired relative cerebral blood flow during reperfusion. Argatroban protects WT mice, but not MBL knockout mice, emphasizing a role of MBL in local thrombus formation in acute ischemia/reperfusion.


Assuntos
Isquemia Encefálica/fisiopatologia , Infarto da Artéria Cerebral Média/fisiopatologia , Lectina de Ligação a Manose/fisiologia , Traumatismo por Reperfusão/fisiopatologia , Trombose/etiologia , Animais , Antitrombinas/administração & dosagem , Arginina/análogos & derivados , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Circulação Cerebrovascular/genética , Modelos Animais de Doenças , Fibrinogênio/antagonistas & inibidores , Fibrinogênio/metabolismo , Infarto da Artéria Cerebral Média/genética , Infarto da Artéria Cerebral Média/metabolismo , Imageamento por Ressonância Magnética , Masculino , Lectina de Ligação a Manose/deficiência , Lectina de Ligação a Manose/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microcirculação/genética , Ácidos Pipecólicos/administração & dosagem , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/metabolismo , Sulfonamidas , Trombose/genética
17.
FEBS Lett ; 588(6): 956-61, 2014 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-24560788

RESUMO

To produce an infection Trypanosoma cruzi must evade lysis by the complement system. During early stages of infection, the lectin pathway plays an important role in host defense and can be activated by binding of mannan-binding lectin (MBL) to carbohydrates on the surface of pathogens. We hypothesized that MBL has a dual role during parasite-host cell interaction as lectin complement pathway activator and as binding molecule to invade the host cell. We used two polarized strains of T. cruzi, R4 (susceptible) and 860 (resistant) strains, to investigate the role of MBL in complement-mediated lysis. Interestingly R4, but not 860 metacyclic strain, markedly increases the invasion of host cells, suggesting that MBL drives the invasion process while the parasite deactivates the Lectin complement pathway.


Assuntos
Lectina de Ligação a Manose/fisiologia , Proteínas de Protozoários/fisiologia , Trypanosoma cruzi/fisiologia , Animais , Doença de Chagas/parasitologia , Chlorocebus aethiops , Ativação do Complemento , Via Alternativa do Complemento , Interações Hospedeiro-Parasita , Humanos , Imunidade Inata , Células Vero
18.
FEBS Lett ; 588(6): 866-72, 2014 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-24530528

RESUMO

Mannan binding lectin (MBL) functions as a pattern recognition molecule (PRM) which is able to initiate complement activation. Here, we characterize a previously unrecognized attribute of MBL as a double-stranded RNA (dsRNA) binding protein capable of modifying Toll like receptor 3 (TLR3) activation. MBL interacts with poly(I:C) and suppresses poly(I:C)-induced activation of TLR3 pathways and subsequent cytokine production. In addition, MBL binds to TLR3 directly. Surprisingly, disrupting the interaction between MBL and complement receptor 1 (CR1) or restraining the traffic of MBL to phagosome reversed the MBL limited TLR3 activation. We demonstrate the importance of MBL guided ligands intracellular localization, emphasizing the significance of understanding the dynamics of TLR agonists complexed with MBL or other PRMs inside the cell in immune defense.


Assuntos
Imunidade Inata , Leucócitos Mononucleares/imunologia , Lectina de Ligação a Manose/fisiologia , RNA de Cadeia Dupla/fisiologia , Receptor 3 Toll-Like/metabolismo , Células Cultivadas , Citocinas/metabolismo , Humanos , Indutores de Interferon/farmacologia , Fatores Reguladores de Interferon/metabolismo , Fagossomos/metabolismo , Poli I-C/farmacologia , Receptores de Complemento 3b/metabolismo , Transdução de Sinais
19.
Pediatr Blood Cancer ; 61(6): 1017-22, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24453114

RESUMO

BACKGROUND: We aimed to investigate whether the presence of mannose binding lectin (MBL2), ficolin 2 (FCN2) polymorphisms or the combined deficiency significantly influence the risk and subsequently the frequency of chemotherapy-induced bacterial infections in children with B acute lymphoblastic leukemia (B-ALL). PROCEDURE: MBL2 polymorphisms for exon 1 and FCN2 polymorphisms for promoter regions -986, -602, -557, -64, -4 and exon 8 regions +6,359, +6,424 were determined in children with B-ALL. FCN2 haplotype was determined by gene sequencing. Number and duration of FN episodes as well as number of bacterial infections were recorded during induction chemotherapy. RESULTS: Forty-four children with B-ALL (median age 4.3 years, 65.9% males) suffered from 142 FN episodes and 92 bacterial infections (40.2% Gram positive and 59.8% Gram negative). MBL2 low-risk genotype was found in 59.1%, medium-risk in 31.8% and high-risk in 9%. FCN2 low-risk haplotypes were detected in 38.2%, medium-risk in 44.1% and high-risk in 17.6%. MBL2 genotype and FCN2 haplotype were not associated with increased frequency of FN episodes. MBL2 medium/high-risk genotype and FCN2 medium/high-risk haplotype were associated with prolonged duration of FN (P = 0.007 and P = 0.001, respectively) and increased number of bacterial infections (P = 0.001 and P = 0.002, respectively). The combined MBL2/FCN2 medium/high-risk genotype was associated with an increased number of bacterial infections (P = 0.001). CONCLUSIONS: MBL2 and FCN2 single or combined deficiencies are associated with increased duration of FN episodes as well as increased number of bacterial infections in children with B-ALL suggesting a prognostic role of these genes.


Assuntos
Infecções Bacterianas/genética , Neutropenia Febril/genética , Lectinas/fisiologia , Lectina de Ligação a Manose/fisiologia , Polimorfismo Genético , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Infecções Bacterianas/etiologia , Criança , Pré-Escolar , Códon/genética , Éxons/genética , Neutropenia Febril/induzido quimicamente , Feminino , Predisposição Genética para Doença , Genótipo , Haplótipos , Humanos , Imunidade Inata , Hospedeiro Imunocomprometido , Lactente , Lectinas/deficiência , Lectinas/genética , Masculino , Lectina de Ligação a Manose/deficiência , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/imunologia , Erros Inatos do Metabolismo/complicações , Erros Inatos do Metabolismo/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/complicações , Risco , Ficolinas
20.
J Immunol ; 192(3): 1294-301, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24391218

RESUMO

Mannan (mannose)-binding protein (MBP) is a C-type serum lectin that plays a key role in innate immunity. MBP forms large multimers (200-600 kDa) and exhibits broad specificity for mannose, N-acetylglucosamine, and fucose. MBP exhibits high affinity for unique oligosaccharides that have been isolated from human colorectal carcinoma (SW1116) cells and characterized as highly fucosylated high m.w. type 1 Lewis glycans. In this study, we first demonstrated that MBP recognizes human primary colorectal carcinoma tissues through tumor-associated MBP ligands. We performed fluorescence-based histochemistry of MBP in human colorectal carcinoma tissues and showed that MBP clearly stained cancer mucosae in a Ca(2+)-dependent manner. Coincubation with plant (Aleuria aurantia) lectin, but not Con A, blocked MBP staining, indicating that fucose, rather than mannose, is involved in this interaction. The expression of MBP ligands was detected in 127 of 330 patients (38.5%), whereas, most significantly, there was no expression in 69 nonmalignant tissues. The MBP-staining pattern in cancer mucosae significantly overlapped with that of Lewis b [Fucα1-2Galß1-3(Fucα1-4)GlcNAc] staining, but the Lewis b staining in normal tissues was not associated with MBP staining. In addition, the MBP staining correlated inversely with the expression of CA19-9 Ag, and MBP stained 11 of 25 (44%) CA19-9 (sialyl Lewis a [NeuAc(α2-3)Galß1-3(Fucα1-4)GlcNAc])(-) colorectal carcinoma tissues. We found a favorable prognosis in patients with MBP ligand(+) tumors. These results suggest that selective recognition of cancer cells by endogenous MBP seems to be associated with an antitumor effect and that tissue staining with MBP in combination with CA19-9 may serve as a novel indicator of colorectal carcinoma tissues.


Assuntos
Adenocarcinoma Mucinoso/química , Adenocarcinoma/química , Antígenos de Neoplasias/análise , Neoplasias Colorretais/química , Lectina de Ligação a Manose/fisiologia , Oligossacarídeos/análise , Adenocarcinoma/diagnóstico , Adenocarcinoma/mortalidade , Adenocarcinoma Mucinoso/diagnóstico , Adenocarcinoma Mucinoso/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígeno CA-19-9/análise , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/mortalidade , Epitélio/química , Técnica Indireta de Fluorescência para Anticorpo , Antígenos HLA-DR/análise , Humanos , Mucosa Intestinal/química , Antígenos do Grupo Sanguíneo de Lewis , Ligantes , Linfócitos do Interstício Tumoral/química , Pessoa de Meia-Idade , Metástase Neoplásica , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais
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