RESUMO
BACKGROUND: The thermodimorphic fungi Paracoccidioides spp. are the etiological agents of paracoccidioidomycosis. Although poorly studied, paracoccin (PCN) from Paracoccidioides brasiliensis has been shown to harbor lectinic, enzymatic, and immunomodulatory properties that affect disease development. METHODS: Mutants of P. brasiliensis overexpressing PCN (ov-PCN) were constructed by Agrobacterium tumefaciens-mediated transformation. ov-PCN strains were analyzed and inoculated intranasally or intravenously to mice. Fungal burden, lung pathology, and survival were monitored to evaluate virulence. Electron microscopy was used to evaluate the size of chito-oligomer particles released by ov-PCN or wild-type strains to growth media. RESULTS: ov-PCN strains revealed no differences in cell growth and viability, although PCN overexpression favored cell separation, chitin processing that results in the release of smaller chito-oligomer particles, and enhanced virulence. Our data show that PCN triggers a critical effect in the cell wall biogenesis through the chitinase activity resulting from overexpression of PCN. As such, PCN overexpression aggravates the disease caused by P. brasiliensis. CONCLUSIONS: Our data are consistent with a model in which PCN modulates the cell wall architecture via its chitinase activity. These findings highlight the potential for exploiting PCN function in future therapeutic approaches.
Assuntos
Parede Celular/metabolismo , Quitina/metabolismo , Proteínas Fúngicas/fisiologia , Lectinas/fisiologia , Paracoccidioides/patogenicidade , Animais , Citocinas/biossíntese , Camundongos , Camundongos Endogâmicos BALB C , Paracoccidioidomicose/imunologia , Fagocitose , VirulênciaRESUMO
Leishmania (Viannia) braziliensis is the main agent of mucocutaneous Leishmaniasis, a neglected tropical disease that affects thousands of people in Brazil. It has been shown that complement plays a critical role at early stages of Leishmania infection and that is involved in the invasion of macrophages by the promastigotes. Ficolins and collectins are soluble pattern recognition and triggering molecules of the lectin complement pathway. We investigated here whether lectin pathway activators ficolin-1, ficolin-2, ficolin-3 and CL-11 bind to live L. braziliensis promastigotes in vitro. Promastigote forms in the stationary growth phase were incubated with normal human serum (NHS) or recombinant ficolins 1, 2 and 3, MBL and CL-11, and protein binding was evaluated by confocal microscopy and flow cytometry. Ficolins 1, 2 and 3, MBL and CL-11 were able to bind to the surface of live promastigotes after incubation with either NHS or recombinant proteins. A partial inhibition by N-acetyl-d-glucosamine characterizing the participation of acetylated groups in the deposition of ficolins and CL-11 to glycoconjugates on the surface of L. braziliensis was observed. These evidences highlight a role for the lectin pathway in the innate response to L. braziliensis.
Assuntos
Colectinas/fisiologia , Lectinas/fisiologia , Leishmania braziliensis/imunologia , Proteínas do Sistema Complemento/fisiologia , Humanos , Imunidade Inata , FicolinasRESUMO
The eggs of the freshwater Pomacea apple snails develop above the water level, exposed to varied physical and biological stressors. Their high hatching success seems to be linked to their proteins or perivitellins, which surround the developing embryo providing nutrients, sunscreens and varied defenses. The defensive mechanism has been unveiled in P. canaliculata and P. maculata eggs, where their major perivitellins are pigmented, non-digestible and provide a warning coloration while another perivitellin acts as a toxin. In P. scalaris, a species sympatric to the former, the defense strategy seems different, since no toxin was found and the major perivitellin, PsSC, while also colored and non-digestible, is a carbohydrate-binding protein. In this study we examine the structure and function of PsSC by sequencing its subunits, characterizing its carbohydrate binding profile and evaluating its effect on gut cells. Whereas cDNA sequencing and database search showed no lectin domain, glycan array carbohydrate binding profile revealed a strong specificity for glycosphingolipids and ABO group antigens. Moreover, PsSC agglutinated bacteria in a dose-dependent manner. Inspired on the defensive properties of seed lectins we evaluated the effects of PsSC on intestinal cells both in vitro (Caco-2 and IEC-6 cells) and in the gastrointestinal tract of rats. PsSC binds to Caco-2 cell membranes without reducing its viability, while a PsSC-containing diet temporarily induces large epithelium alterations and an increased absorptive surface. Based on these results, we propose that PsSC is involved in embryo defenses by altering the gut morphophysiology of potential predators, a convergent role to plant defensive lectins.
Assuntos
Proteínas do Ovo/fisiologia , Ovos , Trato Gastrointestinal , Lectinas/fisiologia , Comportamento Predatório , Ratos , Caramujos/química , Aglutinação , Animais , Células CACO-2 , Células Cultivadas , Trato Gastrointestinal/anatomia & histologia , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/fisiologia , Humanos , Intestinos/anatomia & histologia , Intestinos/efeitos dos fármacos , Intestinos/fisiologia , Lectinas/farmacologia , Masculino , Comportamento Predatório/efeitos dos fármacos , Ratos/anatomia & histologia , Ratos/fisiologia , Ratos WistarRESUMO
La omentina es una nueva adipocina a la que se le ha atribuido la capacidad de regular actividades metabólicas (sensibilidad a la insulina) y antiinflamatorias, ofreciendo protección cardiovascular en la obesidad y diabetes mellitus tipo 2. Por lo anterior, es importante conocer los mecanismos a través de los cuales confiere protección cardiovascular, con el objetivo de considerar la omentina como blanco o agente terapéutico en este escenario.
The omentin is an adipokine, which role is due to the capacity of regulate metabolic (insulin sensitivity) and anti-inflammatory activities, thus conferring vascular protection during obesity and diabetes mellitus type 2. By this, it is important to know the mechanisms by which omentin confers cardiovascular protection, with the purpose of establish omentin a possible therapeutic target or molecule on this scenario.
Assuntos
Humanos , Doenças Cardiovasculares/etiologia , Citocinas/fisiologia , Inflamação/etiologia , Lectinas/fisiologia , Resistência à Insulina/fisiologia , Endotélio Vascular/fisiopatologia , Metabolismo Energético , Proteínas Ligadas por GPI/fisiologia , Obesidade/etiologiaRESUMO
The omentin is an adipokine, which role is due to the capacity of regulate metabolic (insulin sensitivity) and anti-inflammatory activities, thus conferring vascular protection during obesity and diabetes mellitus type 2. By this, it is important to know the mechanisms by which omentin confers cardiovascular protection, with the purpose of establish omentin a possible therapeutic target or molecule on this scenario.
Assuntos
Doenças Cardiovasculares/etiologia , Citocinas/fisiologia , Inflamação/etiologia , Resistência à Insulina/fisiologia , Lectinas/fisiologia , Endotélio Vascular/fisiopatologia , Metabolismo Energético , Proteínas Ligadas por GPI/fisiologia , Humanos , Obesidade/etiologiaRESUMO
Introdução e objetivos: O glioblastoma multiforme é um glioma de alto grau que apresenta um prognóstico ruim. O diagnóstico definitivo é estabelecido pela avaliação histológica, porém este pode apresentar conflitos na classificação, com isso surge à necessidade de ferramentas que auxiliem o patologista em sua análise. Atualmente, maior ênfase tem sido dada a alterações na glicosilação, pois estão associadas a neoplasias, e a descoberta da capacidade de lectinas em reconhecer tais alterações fez destas, ferramentas aplicáveis para o diagnóstico biomédico. Dessa forma, o objetivo deste trabalho é analisar a marcação das lectinas CpL, WGA e Con A em células da linhagem C6...
Introduction and objectives: Glioblastoma multiforme is a high-grade glioma that has a poor prognosis. The definitive diagnosis is established by histological assessment. However, this can present conflicts in grading gliomas, which justifies new tools to assist the pathologist in his analysis. Currently, it is known that there are changes in glycosylation pattern of molecules associated with cancer, and the discovery of the ability of lectins to recognize these changes made these tools applicable for biomedical diagnosis. Thus, the aim of this study is to analyze the labelling of C6...
Assuntos
Humanos , Glioma/complicações , Glioma/diagnóstico , Glioma/imunologia , Glioma/patologia , Glioma/sangue , Lectinas , Lectinas/análise , Lectinas/fisiologia , Lectinas/imunologiaRESUMO
Paracoccin is an N-acetyl-glucosamine-binding lectin from Paracoccidioides brasiliensis, which can be obtained in small amounts either from culture supernatants or yeast cell extracts. In the present work, immunoelectron microscopy with mouse anti-paracoccin IgG localized the antigen to the cell wall of P. brasiliensis yeast forms. Paracoccin interacted with chitin, and colocalized with beta-1,4-homopolymer of GlcNAc to the budding sites of P. brasiliensis yeast cell. In order to evaluate the role of paracoccin on fungal growth, yeast cells were cultivated in the presence of anti-paracoccin antibodies. A significant reduction of both colony forming units and individual yeast cells was observed as well as morphological alterations such as smaller colonies and cells more loosely aggregated than in control cultures without the antibody. A role of paracoccin on the cell wall organization was reinforced by alterations in the labeling pattern of chitin when yeasts were treated with anti-paracoccin antibodies. Binding of specific antibodies to paracoccin may disrupt the paracoccin/chitin interactions, resulting in the inhibition of P. brasiliensis growth.
Assuntos
Proteínas Fúngicas/fisiologia , Lectinas/fisiologia , Paracoccidioides/crescimento & desenvolvimento , Acetilglucosamina/metabolismo , Animais , Parede Celular/metabolismo , Quitina/metabolismo , Microscopia Eletrônica , Paracoccidioides/metabolismoRESUMO
Alectina ligante de manose (MBL) e uma proteina com importantepapel na primeira linha de defesa do sistema imune inato, cujos valores sericos sao determinados geneticamente. A MBL ativa a via da lectina do complemento, alem de mediar a opsonisaçao e fagocitose de microorganismos. A hanseniase e uma doença infecciosa cronica causada pelo Mycobacterium leprae, bacteria intracelular obrigatoria, que infecta fagocitos mononucleares do ospedeiro...
Assuntos
Humanos , Hanseníase/fisiopatologia , Hanseníase/imunologia , Hanseníase/microbiologia , Lectinas/fisiologia , Lectinas/imunologia , Mycobacterium leprae/citologia , Mycobacterium leprae/fisiologia , Mycobacterium leprae/imunologia , Dolicol Monofosfato Manose , Dolicol Monofosfato Manose/imunologiaRESUMO
It was found that Azospirillum brasilensis strain Sp7 is able to produce extracellular proteolytic enzymes. The enzymes were active within a broad range of pH values, with two peaks of activity being located in the acid and alkaline pH areas; required calcium ions; and exhibited substrate specificity with respect to azogelatin. Zymography allowed at least four proteolytic enzymes with molecular weights of 32, 45, 52, and 174 kDa to be detected in A. brasilense Sp7 culture liquid. It was shown that the lectin from A. brasilense Sp7 can inhibit proteolytic enzymes.
Assuntos
Azospirillum/enzimologia , Lectinas/fisiologia , Peptídeo Hidrolases/metabolismo , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Hidrólise , Peso Molecular , Peptídeo Hidrolases/química , Inibidores de Proteases/farmacologia , Especificidade por SubstratoRESUMO
The Entamoeba histolytica Ehcp112 and Ehadh112 genes that encode the EhCPADH complex are separated by a non-coding 188pb region. Their proximity suggests a coordinated expression regulation for both genes. Here, we studied the structure and function of 996 bp (p996CAT) upstream the ATG start codon of the Ehadh112 gene. The p996CAT plasmid drove CAT transcription with a 78% of the activity showed by actin promoter. Deletion of 330 bp at the 5' end of p966CAT to produce the p776CAT plasmid, decreased activity to 40% in relation to actin promoter and to 50% of p996CAT, suggesting the presence of a silencer in this region. Interestingly, deletion of other 297 bp to the p776CAT to generate the p469CAT plasmid, augmented activity in 2.5-fold compared with p776CAT construction, showing the presence of a proximal enhancer promoter. Transcription initiation sites (-69 and -150 bp), TATA like box, GAAC, and Inr elements, as well as putative DNA binding motifs, were mapped in the -1 to -469 bp core promoter region.