RESUMO
Diabetes mellitus (DM) is a chronic systemic disease characterized by a multifactorial nature, which may lead to several macro and microvascular complications. Diabetic retinopathy (DR) is one of the most severe microvascular complications of DM, which can result in permanent blindness. The mechanisms involved in the pathogenesis of DR are multiple and still poorly understood. Factors such as dysregulation of vascular regeneration, oxidative and hyperosmolar stress in addition to inflammatory processes have been associated with the pathogenesis of DR. Furthermore, compelling evidence shows that components of the immune system, including the complement system, play a relevant role in the development of the disease. Studies suggest that high concentrations of mannose-binding lectin (MBL), an essential component of the complement lectin pathway, may contribute to the development of DR in patients with DM. This review provides an update on the possible role of the complement system, specifically the lectin pathway, in the pathogenesis of DR and discusses the potential of MBL as a non-invasive biomarker for both, the presence and severity of DR, in addition to its potential as a therapeutic target for intervention strategies.
Assuntos
Biomarcadores , Retinopatia Diabética , Lectina de Ligação a Manose , Humanos , Retinopatia Diabética/imunologia , Retinopatia Diabética/etiologia , Retinopatia Diabética/metabolismo , Retinopatia Diabética/diagnóstico , Lectina de Ligação a Manose/metabolismo , Animais , Lectina de Ligação a Manose da Via do Complemento , Suscetibilidade a Doenças , Ativação do Complemento/imunologiaRESUMO
BACKGROUND: Leishmaniasis is caused by an intracellular protozoan of the Leishmania genus. Mannose-binding lectin (MBL) is a serum complement protein and recognizes lipoprotein antigens in protozoa and the bacterial plasma membrane. Nucleotide variants in the promoter region and exon 1 of the MBL gene can influence its expression or change its molecular structure. OBJECTIVE: To evaluate, through a systematic review, case-control studies of the genetic association of variants in the MBL2 gene and the risk of developing leishmaniasis. METHODS: This review carried out a search in PubMed, Science Direct, Cochrane Library, Scopus and Lilacs databases for case-control publications with six polymorphisms in the mannose-binding Lectin gene. The following strategy was used: Pâ¯=â¯Patients at risk of leishmaniasis; Iâ¯=â¯Presence of polymorphisms; Câ¯=â¯Absence of polymorphisms; Oâ¯=â¯Occurrence of leishmaniasis. Four case/control studies consisting of 791 patients with leishmaniasis and 967 healthy subjects (Control) are included in this meta-analysis. The association of variants in the mannose-binding Lectin gene and leishmaniasis under the allelic genetic model, -550 (Hvs. L), -221 (X vs. Y), +4 (Q vs. P), CD52 (A vs. D), CD54 (A vs. B), CD57 (A vs. C) and A/O genotype (A vs. O) was evaluated. International Prospective Register of Systematic Reviews (PROSPERO): CRD42020201755. RESULTS: The meta-analysis results for any allelic genetic model showed no significant association for the variants within the promoter, the untranslated region, and exon 1, as well as for the wild-type A allele and mutant allele O with leishmaniasis. STUDY LIMITATIONS: Caution should be exercised when interpreting these results, as they are based on a few studies, which show divergent results when analyzed separately. CONCLUSIONS: This meta-analysis showed a non-significant association between the rs11003125, rs7096206, rs7095891, rs5030737, rs1800450, and rs1800451 polymorphisms of the Mannose-binding Lectin gene and leishmaniasis in any allelic and heterogeneous evaluation.
Assuntos
Leishmaniose , Lectina de Ligação a Manose , Alelos , Predisposição Genética para Doença/genética , Genótipo , Humanos , Leishmaniose/genética , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/metabolismo , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
The biomolecular recognition of D-mannose-binding lectin from Artocarpus heterophyllus (ArtinM) by Horseradish Peroxidase (HRP) mediated by glycosylation allows their application in a multitude of biological systems. The present work describes the use of molecular dynamics (MD) to assess the Gibbs free energy associated with the formation of a ArtinM-HRP conjugate mediated by a glycosylation molecule. For the enthalpy term, we applied the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method and for the vibrational entropy term, we use the quasi-harmonic approximation. Our results show that, even without glycosylation, the binding free energy between ArtinM and HRP is - 196.154 kJmol- 1, an extremely high affinity with low selectivity, originated mainly through the van der Waals energy terms. The binding free energy between ArtinM and the glycosylated HRP (gHRP) was calculated at - 66.156 kJmol- 1, an absolute and considerably lower value, however, originated from electrostatic energy terms, which increases the selectivity of molecular recognition. Our work has shown that the HRP active site region has a high affinity and low selectivity for other biomolecules. The presence of glycosylation plays a role in increasing this selectivity for this region. Thus, we conclude that performing mutagenesis of amino acid residues near the entrance of the catalytic site, can improve the activity of non-glycosylated HRPs. This illustrates new insights that can be applied to carbohydrate-based immunochemistry.
Assuntos
Artocarpus/metabolismo , Lectina de Ligação a Manose/metabolismo , Simulação de Dinâmica Molecular , Glicosilação , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Lectina de Ligação a Manose/química , Lectinas de Plantas , TermodinâmicaRESUMO
Free-living amoebae (FLAs) are major reservoirs for a variety of bacteria, viruses, and fungi. The most studied mycophagic FLA, Acanthamoeba castellanii (Ac), is a potential environmental host for endemic fungal pathogens such as Cryptococcus spp., Histoplasma capsulatum, Blastomyces dermatitides, and Sporothrix schenckii. However, the mechanisms involved in this interaction are poorly understood. The aim of this work was to characterize the molecular instances that enable Ac to interact with and ingest fungal pathogens, a process that could lead to selection and maintenance of possible virulence factors. The interaction of Ac with a variety of fungal pathogens was analysed in a multifactorial evaluation that included the role of multiplicity of infection over time. Fungal binding to Ac surface by living image consisted of a quick process, and fungal initial extrusion (vomocytosis) was detected from 15 to 80 min depending on the organism. When these fungi were cocultured with the amoeba, only Candida albicans and Cryptococcus neoformans were able to grow, whereas Paracoccidioides brasiliensis and Sporothrix brasiliensis displayed unchanged viability. Yeasts of H. capsulatum and Saccharomyces cerevisiae were rapidly killed by Ac; however, some cells remained viable after 48 hr. To evaluate changes in fungal virulence upon cocultivation with Ac, recovered yeasts were used to infect Galleria mellonella, and in all instances, they killed the larvae faster than control yeasts. Surface biotinylated extracts of Ac exhibited intense fungal binding by FACS and fluorescence microscopy. Binding was also intense to mannose, and mass spectrometry identified Ac proteins with affinity to fungal surfaces including two putative transmembrane mannose-binding proteins (MBP, L8WXW7 and MBP1, Q6J288). Consistent with interactions with such mannose-binding proteins, Ac-fungi interactions were inhibited by mannose. These MBPs may be involved in fungal recognition by amoeba and promotes interactions that allow the emergence and maintenance of fungal virulence for animals.
Assuntos
Acanthamoeba castellanii/metabolismo , Fungos/patogenicidade , Lectina de Ligação a Manose/metabolismo , Acanthamoeba castellanii/química , Acanthamoeba castellanii/microbiologia , Acanthamoeba castellanii/ultraestrutura , Animais , Candida albicans/patogenicidade , Candida albicans/ultraestrutura , Concanavalina A/metabolismo , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/ultraestrutura , Histoplasma/patogenicidade , Histoplasma/ultraestrutura , Interações Hospedeiro-Patógeno , Larva/microbiologia , Lepidópteros/microbiologia , Manose/química , Manose/metabolismo , Lectina de Ligação a Manose/química , Espectrometria de Massas , Microscopia Eletrônica de Varredura , Paracoccidioides/patogenicidade , Paracoccidioides/ultraestrutura , Saccharomyces cerevisiae/patogenicidade , Saccharomyces cerevisiae/ultraestrutura , Fatores de Tempo , Imagem com Lapso de Tempo , Virulência , Fatores de Virulência/metabolismoRESUMO
Mannose-binding lectin (MBL) plays important roles by interacting with specific molecular patterns on cell surfaces, triggering first-line host defense. We investigated the MBL interaction with healthy red blood cell membranes as well as its effects on the membrane rheology. We explored electrostatic interactions between cationic quantum dots (QDs) and negatively charged red blood cell surfaces to quantitatively evaluate membrane electrical charges as well as to investigate the MBL binding to healthy erythrocytes. Results showed that cationic QDs labeled efficiently red blood cells. However, the MBL interaction with erythrocytes prevents the QD labeling. We also observed that red blood cells treated with MBL are more resistant to lysis, suggesting a membrane-stabilizing effect. Moreover, we used a fluorescent anti-MBL antibody and Candida albicans cells to further study the MBL interaction with erythrocytes. Our results of this comparative labeling suggested that either this probe was not effective to detect MBL bound to healthy red blood cells (by its carbohydrate-recognition domain) or the MBL binding to those cells might be occurring via another portion. Thus, our results demonstrated the ability of MBL interacting with healthy red blood cells and pointed out to a new role of this protein as a membrane-stabilizing molecule.
Assuntos
Cátions/metabolismo , Eritrócitos/metabolismo , Lectina de Ligação a Manose/metabolismo , Pontos Quânticos , Candida albicans , Candidíase , Eritrócitos/ultraestrutura , Citometria de Fluxo , Hemólise , Humanos , Microscopia de FluorescênciaRESUMO
AIMS: Mannose-binding lectin (MBL) is a protein synthesized by the liver and its immune response is associated with the development of liver fibrosis. We hypothesized that the polymorphisms in the Exon 1 region (52, 54, 57) and promoter regions (-550 H/L, -221 X/Y) of the MBL2 gene were associated with the severity of periportal fibrosis (PPF), and that these polymorphisms affect the MBL serum levels. MATERIALS AND METHODS: In this cross-sectional study we genotyped these polymorphisms within the MBL2 gene in 229 Brazilian subjects infected with Schistosoma mansoni, with different patterns of PPF. RESULTS: There was no association between the polymorphisms and haplotypes of the MBL2 gene and the advanced PPF pattern. The MBL levels were higher in individuals with advanced fibrosis. There was risk association among high-expression haplotypes of MBL, and a protection association between the A/O Exon 1 genotype and elevated MBL serum levels. CONCLUSIONS: Our results suggest that polymorphism of Exon 1 and MBL haplotypes could potentially be used to predict the severity of advanced PPF in the Brazilian population.
Assuntos
Cirrose Hepática/genética , Lectina de Ligação a Manose/genética , Esquistossomose/genética , Adulto , Brasil , Estudos Transversais , Etnicidade/genética , Éxons/genética , Feminino , Fibrose , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Haplótipos , Humanos , Masculino , Lectina de Ligação a Manose/sangue , Lectina de Ligação a Manose/metabolismo , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Regiões Promotoras Genéticas/genética , Esquistossomose/metabolismoRESUMO
The present study investigated the frequencies of rs1800450 (MBL âB, G>A), rs1800451 (MBL âC, G>A), and rs5030737 (MBL âD, C>T) polymorphisms in exon 1 of the MBL2 gene among patients with chronic viral hepatitis. Blood samples from patients infected with hepatitis B virus (HBV; n = 65), hepatitis C virus (HCV; n = 92), and a noninfected control group (n = 300) were investigated. The presence of polymorphisms was detected using a real-time polymerase chain reaction to correlate with liver disease pathogenesis and fibrosis staging according to the Metavir classification. The genotypic and allelic frequencies showed no significant differences between the groups, but patients with active HBV and the wild AA genotype presented a positive correlation between increased transaminase and HBV DNA levels and the presence of mild to moderate fibrosis. Patients with HCV and the wild AA genotype presented mild inflammation and higher HCV RNA levels, although the same association was not observed for the fibrosis scores. The results suggest that the mutations in exon 1 of the MBL2 gene do not contribute directly to the clinical and laboratory features of HCV and HBV infections, but further studies should be performed to confirm whether the wild AA genotype has indirect effect on disease progression.
Assuntos
Vírus da Hepatite B/patogenicidade , Fígado/enzimologia , Fígado/virologia , Lectina de Ligação a Manose/metabolismo , Carga Viral/fisiologia , Adulto , Idoso , Estudos Transversais , Éxons/genética , Feminino , Frequência do Gene/genética , Frequência do Gene/fisiologia , Genótipo , Vírus da Hepatite B/genética , Humanos , Fígado/metabolismo , Masculino , Lectina de Ligação a Manose/genética , Pessoa de Meia-IdadeRESUMO
Blood levels of regulators of the complement system in preterm babies were reported in few studies only. The aim of this study was to set up a complement profile in premature and term babies focusing on the development of blood levels of MBL, key regulatory proteins and on classical pathway activity, which may allow an estimation of potential susceptibility to infection. Complement activity (CH50), levels of mannan-binding lectin (MBL), complement regulators (factors H and I, C1 inhibitor, properdin) and C3a as marker of complement activation were assessed in three groups of healthy newborns: (1) prematures (≤34 weeks); (2) late prematures (>34-<37 weeks) and (3) term neonates (≥37 weeks). CH50 increased with gestational age with lower titres in cord blood than in day 5 post-delivery venous blood. MBL concentrations were not significantly different among groups. Quantitative and functional C1 inhibitor were below adult normal range in prematures <34 weeks and lower in cord blood as compared to day 5. Factor I, factor H and properdin remained below adult values in all groups. Low C3a levels excluded that low complement titres were due to activation-induced consumption. These results demonstrate the relative immaturity of the complement system and its regulation, especially in premature infants.
Assuntos
Proteína Inibidora do Complemento C1/metabolismo , Complemento C3a/metabolismo , Nascimento Prematuro/imunologia , Adulto , Ativação do Complemento , Proteína Inibidora do Complemento C1/genética , Complemento C3a/genética , Fator H do Complemento/genética , Fator H do Complemento/metabolismo , Ensaio de Atividade Hemolítica de Complemento , Feminino , Fibrinogênio/genética , Fibrinogênio/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Idade Gestacional , Humanos , Recém-Nascido , Lectina de Ligação a Manose/genética , Lectina de Ligação a Manose/metabolismo , Gravidez , Properdina/genética , Properdina/metabolismoRESUMO
Mannose-binding lectin (MBL) and Toll-like receptor (TLR) polymorphisms may influence susceptibility and manifestation of Trypanosoma cruzi infection. In northern Chile, we examined 61 asymptomatic patients with chronic Chagas disease (CD), 64 patients with chronic Chagas cardiomyopathy (CCC), and 45 healthy individuals. Low-producer MBL2*B genotypes were more common in CD patients (48%) than healthy individuals (31%; adjusted odds ratio = 2.3, 95% confidence interval = 1.01-5.4, P = 0.047) but did not differ with manifestation. In contrast, the heterozygous Toll-like receptor 4 (TLR4)-deficiency genotype D299G/T399I occurred more frequently in asymptomatic (14.8%) than CCC patients (3.1%; P = 0.02). TLR1-I602S, TLR2-R753Q, TLR6-S249P, and MAL/TIRAP-S180L did not associate with CD or CCC. These findings support the complement system to be involved in defense against Trypanosoma cruzi infection and indicate that curbed TLR4 activation might be beneficial in preventing CCC.
Assuntos
Cardiomiopatia Chagásica/epidemiologia , Cardiomiopatia Chagásica/genética , Lectina de Ligação a Manose/genética , Polimorfismo de Nucleotídeo Único , Receptor 4 Toll-Like/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Cardiomiopatia Chagásica/imunologia , Criança , Pré-Escolar , Chile/epidemiologia , Doença Crônica , Suscetibilidade a Doenças , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Heterozigoto , Humanos , Imunidade Inata , Lactente , Masculino , Lectina de Ligação a Manose/metabolismo , Pessoa de Meia-Idade , Receptor 4 Toll-Like/metabolismo , Adulto JovemRESUMO
The aim of this work was to purify and partially characterize a mannose recognition lectin from Nile tilapia (Oreochromis niloticus) serum, named OniL. OniL was isolated through precipitation with ammonium sulfate and affinity chromatography (Concanavalin A-Sepharose 4B). In addition, we evaluated carbohydrate specificity, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profiles, and in vitro immunomodulatory activity on mice splenocyte experimental cultures through cytotoxic assays and cytokine production. The ammonium sulfate fraction F2 showed the highest specific hemagglutinating activity (331) and was applied to affinity matrix. Adsorbed proteins (OniL) were eluted with methyl-α-D: -mannopyranoside. OniL, a 17-kDa protein by SDS-PAGE constituted by subunits of 11 and 6.6 kDa, showed highest affinity for methyl-α-D: -mannopyranoside and D: -mannose. Immunological assays, in vitro, showed that OniL did not show cytotoxicity against splenocytes, induced higher IFN-γ production and lower IL-10 as well as nitrite release. In conclusion, OniL lectin was successfully purified and showed a preferential Th1 response in mice splenocytes.