The effect of Cratylia floribunda lectin on renal hemodynamics and ion transport

As lectinas são descritas como (glico)proteínas que se ligam, especificamente e reversivelmente, a carboidratos. Lectinas de leguminosas isoladas da subtribo Diocleinae (Canavalia, Dioclea eCratylia) são estruturalmente homólogas em relação às suas estruturas primárias. Demonstrou-se que as lectinas de DiocleinaeCanavalia brasiliensis, Dioclea guianensis eCanavalia ensiformis alteram diferentemente parâmetros fisiológicos em rins isolados de ratos. Dessa maneira, o objetivo deste estudo foi investigar o papel da lectina de Cratylia floribunda (CFL) na hemodinâmica renal e no transporte de íons em ratos. Em rins isolados perfundidos, CFL (10 mg/mL, n=5) aumentou a pressão de perfusão renal, a resistência vascular renal e reduziu o percentual do transporte tubular de K+, mas não alterou o fluxo urinário, a taxa de filtração glomerular e o percentual de transporte tubular dos íons sódio e cloreto. No leito mesentérico isolado perfundido, CFL (3 e 10 mg/mL/min, n=4) não alterou o tônus basal ou a contração do tecido induzida por fenilefrina (1 mM/mL/min). Em conclusão, a lectina de sementes de Cratylia floribunda altera parâmetros hemodinâmicos renais, provavelmente de origem tubular, e não por alterações hemodinâmicas.Lectins have been described as glycoproteins that reversibly and specifically bind to carbohydrates. Legume lectins isolated from the subtribe Diocleinae (Canavalia, Dioclea andCratylia) are structurally homologous with respect to their primary structures. The Diocleinae lectins of Canavalia brasiliensis, Dioclea guianensis andCanavalia ensiformis have been shown to distinctly alter physiological parameters in isolated rat kidneys. Thus, the aim of this study was to investigate the effect of Cratylia floribunda lectin (CFL) on renal hemodynamics and ion transport in rats. In isolated perfused kidneys, CFL (10 mg/mL, n=5) increased RPP, RVR and decreased %TK+, but did not change urinary flow, glomerular filtration rate, sodium or chloride tubular transport. In isolated perfused mesenteric bed, CFL (3 and 10 mg/mL/min; n=4) did not alter tissue basal tonus or tissue contraction by phenylephrine (1 mM/mL/min). In conclusion, the seed lectin of Cratylia floribunda increased renal hemodynamic parameters showing a kaliuretic effect. This effect could be of tubular origin, rather than a result from haemodynamic alterations

A novel vasorelaxant lectin purified from seeds of Clathrotropis nitida: Partial characterization and immobilization in chitosan beads

A novel lectin from seeds of Clathrotropis nitida (CNA) was purified and characterized. CNA is a glycoprotein containing approximately 3.3% carbohydrates in its structure. CNA promoted intense agglutination of rabbit erythrocytes, which was inhibited by galactosides and porcine stomach mucin (PSM). The lectin maintained its hemagglutinating activity after incubation in a wide range of temperatures (30-60 °C) and pH (6.0-7.0), and its binding activity was dependent on divalent cations (Ca+2 and Mg+2). SDS-PAGE showed an electrophoretic profile consisting of a single band of 28 kDa, as confirmed by electrospray ionization mass spectrometry, which indicated an average molecular mass of 27,406 ± 2 Da and the possible presence of isoforms and glycoforms. In addition, CNA exhibited no toxicity to Artemia sp. nauplii and elicited reversible and dose-dependent vasorelaxation in precontracted aortic rings. CNA was successfully immobilized on chitosan beads and was able to capture PSM in solution. This study demonstrated that CNA is a lectin that has potential as a biotechnological tool in glycomics and glycoproteomics applications. © 2015 Elsevier Inc

Structural basis for both pro- and anti-inflammatory response induced by mannose-specific legume lectin from Cymbosema roseum

Legume lectins, despite high sequence homology, express diverse biological activities that vary in potency and efficacy. In studies reported here, the mannose-specific lectin from Cymbosema roseum (CRLI), which binds N-glycoproteins, shows both pro-inflammatory effects when administered by local injection and anti-inflammatory effects when by systemic injection. Protein sequencing was obtained by Tandem Mass Spectrometry and the crystal structure was solved by X-ray crystallography using a Synchrotron radiation source. Molecular replacement and refinement were performed using CCP4 and the carbohydrate binding properties were described by affinity assays and computational docking. Biological assays were performed in order to evaluate the lectin edematogenic activity. The crystal structure of CRLI was established to a 1.8 Å resolution in order to determine a structural basis for these differing activities. The structure of CRLI is closely homologous to those of other legume lectins at the monomer level and assembles into tetramers as do many of its homologues. The CRLI carbohydrate binding site was predicted by docking with a specific inhibitory trisaccharide. CRLI possesses a hydrophobic pocket for the binding of α-aminobutyric acid and that pocket is occupied in this structure as are the binding sites for calcium and manganese cations characteristic of legume lectins. CRLI route-dependent effects for acute inflammation are related to its carbohydrate binding domain (due to inhibition caused by the presence of α-methyl-mannoside), and are based on comparative analysis with ConA crystal structure. This may be due to carbohydrate binding site design, which differs at Tyr12 and Glu205 position. © 2011 Elsevier Masson SAS. All rights reserved

Contribution of the carbohydrate-binding ability of Vatairea guianensis lectin to induce edematogenic activity

Vatairea guianensis lectin (VGL), Dalbergiae tribe, is a N-acetyl-galactosamine (GalNAc)/Galactose (Gal) lectin previously purified and characterized. In this work, we report its structural features, obtained from bioinformatics tools, and its inflammatory effect, obtained from a rat paw edema model. The VGL model was obtained by homology with the lectin of Vatairea macrocarpa (VML) as template, and we used it to demonstrate the common characteristics of legume lectins, such as the jellyroll motif and presence of a metal-binding site in the vicinity of the carbohydrate-recognition domain (CRD). Protein-ligand docking revealed favorable interactions with N-acetyl-D-galactosamine, D-galactose and related sugars as well as several biologically relevant N- and O-glycans. In vivo testing of paw edema revealed that VGL induces edematogenic effect involving prostaglandins, interleukins and VGL CRD. Taken together, these data corroborate with previous reports showing that VGL interacts with N- and/or O-glycans of molecular targets, particularly in those presenting galactosides in their structure, contributing to the lectin inflammatory effect. © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM

USO DE EXTRATOS DE POLISSACARÍDICOS DA PLANTA MEDICINAL CAESALPINEA FERREA NA ESTIMULAÇÃO DO EDEMA NA PATA DE RATOS

The innate system is able to promote immediate inflammatory response to injuries, acting as an initial defense mechanism, being its failing associated to exacerbated response as asthma or to deficiencies, that lead to rapid serious infection. Thus, the better understanding of this process as well as the use of modulatory molecules is extremely important. Plant polysaccharides are recognized for its antiviral, antitumor, immunostimulant, anti-inflammatory and anticoagulant effects. Polysaccharide extract obtained from Caesalpinia ferrea barks, a plant widely is used in folk medicine for wound healing, among others. This effect had been confirmed for the polysaccharide extract obtained from its barks. The present study evaluated the inflammatory activity of polyssaccharide extracts obtained from barks (PEB), pods (PEP) and leaves (PEL) of Caesalpinia ferrea. The plant was collected at Custódio, Quixadá-CE for obtention of the polyssaccharide extracts. Barks, pods and leaves were suspended in methanol, re-suspended in 0.1 M NaOH, neutralized with 1 M HCl and evaluated for carbohydrate and protein content. PEB, PEP and PEL were tested in female Wistar rats (150-250g) in the model of paw edema induced by subcutaneous (s.c.) intraplantar administration of dextran (300 µg), carrageenan (300 µg) or polyssaccharide extracts (0.01, 0.1 e 1 mg/kg) and measured by plesthysmometry (0 - 8h). C. ferrea polyssaccharide extracts presented high content of carbohydrate (PEB: 44%; PEP: 31%; PEL: 44%) and edematogenic activity, with maximal efficacy at 1 mg/kg: PEB (0.75±0.05 mL vs. saline: 0.45±0.04 mL); PEP (0.46±0.06 mL; vs saline: 0.16±0.02 mL); PEL (0.3±0.01 mL; saline: 0.18±0.02 mL). In addition, the edematogenic effect presented by the extracts were inferior compared to those induced by the flogistic agents carrageenan or dextran: PEB: 1.5x vs. carrageenan (93.7±6.1) and 1.2x vs. dextran (76.5±5.0); PEP: 1.6x vs. carrageenan (82.5±6.1) and 3.9x to dextran (76.5±5.0); PEL: 2.8x inferior to carrageenan (93.7±6.1) and 2.1x vs. dextran (76.5±5.0). In conclusion PEB, PEP and PEL induce edematogenic effect at different degrees in rat, being that of PEL of minor intensity, suggesting its use as immunostimulant.O sistema imune inato é capaz de promover respostas inflamatórias imediatas a lesões e atua como mecanismo inicial de defesa no corpo, estando seus defeitos associados a respostas exacerbadas, como na asma, ou a deficiências que levam a infecções graves, de aparecimento rápido. Assim, um melhor entendimento do processo inflamatório, bem como a utilização de moléculas modulatórias é de extrema importância. Polissacarídeos de plantas são reconhecidos por suas atividades antiviral, antitumoral, imunoestimulante, anti-inflamatória e anticoagulante. O extrato polissacarídico da casca de Caesalpinia ferrea (Caesalpinioideae), planta muito utilizada na medicina popular, possui efeito cicatrizante de feridas. O presente estudo avaliou a atividade inflamatória de extratos polissacarídicos obtidos da casca (EPC), vagens (EPV) e folhas (EPF) de Caesalpinia ferrea. A planta foi coletada em Custódio, município de Quixadá-CE, para extração dos polissacarídeos. Casca, vagens e folhas foram suspensas em metanol, ressuspensas em NaOH (0,1 M), neutralizadas com HCl (1 M) e avaliadas quanto aos teores de carboidrato e proteína. EPC, EPV e EPF foram testados em ratos Wistar fêmeas (150-250g) no modelo de edema de pata, induzido pela administração subcutânea (s.c.) intraplantar de dextrana (300 µg), carragenana (300 µg) ou dos extratos polissacarídicos (0,01, 0,1 e 1 mg/kg), e mensurado por plestismometria (0-8 horas). Os extratos polissacarídicos apresentaram elevado teor de carboidratos (EPC: 44%; EPV: 31%; EPF: 44%) e atividade edematogênica, com maior eficácia na dose de 1 mg/kg: EPC (0,75±0,05 mL vs. salina: 0,45±0,04 mL); EPV (0,46±0,06 mL; vs salina: 0,16±0,02 mL); EPF (0,3±0,01 mL; salina: 0,18±0,02 mL). Além disso, o efeito edematogênico apresentado pelos extratos foram inferiores aos dos induzidos pelos agentes flogísticos carragenana e dextrana: EPC: 1,5x vs. carragenana (93,7±6,1) e 1,2x vs. dextrana (76,5±5,0); EPV: 1,6x vs. carragenana (82,5±6,1) e 3,9x vs. dextrana (76,5±5,0); EPF: 2,8x vs. carragenana (93,7±6,1) e 2,1x vs. dextrana (76,5±5,0). Conclui-se que EPC, EPV e EPF apresentam efeito edematogênico em grau diferenciado em ratos, sendo o do EPF de menor intensidade, sugerindo seu uso como imunoestimulante

<b>Protective effects of ethanolic extract from the red algae <i>Amansia multifida</i> on experimental inflammation, nociception and seizure experimental models

This study aimed to investigate the EEAm effect in mice models of nociception, inflammation and in behavioral tests evaluating the central nervous system. EEAm had inhibitory effects in the following tests: acetic acid-induced writhing (78%); formalin (62% - inflammatory phase); open field (46%). EEAm increased the nociceptive latency (56%) in tail flick test and increased the death-latency by 36% in the pentylenetetrazole-induced seizure model. Moreover, EEAm inhibited paw edema (82%) and peritonitis (45%) induced by carrageenan. In conclusion, EEAm presents antinociceptive, anti-inflammatory and anticonvulsant effects involving peripheral and central-acting mechanisms in mice.

Polysaccharide extract of Mimosa tenuiflora stem barks stimulates acute inflammatory response via nitric oxide

Mimosa tenuiflora (Mimosaceae) or “jurema-preta” is well distributed in the northeast Brazil, being popularly used to treat skin lesions, burns and inflammation. The healing effect of the alcoholic extract prepared with its barks corroborates the popular use. This study aimed to evaluate the inflammatory response of polysaccharides extracted from M. tenuiflora barks (EP-Mt) by methanol/NaOH and ethanol precipitation. Inflammatory activity was assessed in rat models of acute inflammation (paw edema and peritonitis), by the following parameters: edema, vascular permeability, leukocyte migration, myeloperoxidase activity and pharmacological modulation of nitric oxide and prostaglandins. EP-Mt presented 3.8% yield, 41% carbohydrate and 0.34% protein. EP-Mt (0.01, 0.1, 1.0 mg kg-1) injected by subcutaneous route elicited paw edema that lasted from 30-420 min, with maximal effect at 1 mg kg-1 (40x vs. saline), and was inhibited by L-NAME (52%) and dexamethasone (26%). EP-Mt (1 mg kg-1, via intraperitoneal) stimulated leukocytes migration (2.2x), mainly neutrophils (6.5x) and MPO activity (96%). The leukocyte migration elicited by EP-Mt was inhibited by dexamethasone (39%) and L-NAME (38%). EP-Mt containing high carbohydrate content induces acute inflammation via nitric oxide, which open perspectives of application in pathological conditions of immunosuppression.

CRLI induces vascular smooth muscle relaxation and suggests a dual mechanism of eNOS activation by legume lectins via muscarinic receptors and shear stress

Lectins are proteins able to recognize carbohydrates, without modifying their structure, via the carbohydrate-recognition domain (CRD). Here, the three-dimensional structure of the mannose-binding lectin isolated from Cymbosema roseum (CRLI) was determined with X-man molecule modeled into the carbohydrate recognition domain. CRLI relaxant activity in thoracic rat aorta was also investigated, and based on the results, a molecular docking of CRLI with heparan sulfate was performed to investigate the possible interaction with mechanoreceptors involved in vasorelaxation. CRLI (IC50 = 12.4 μg mL-1) elicited vasorelaxant response (96%) in endothelialized rat aorta contracted with phenylephrine. Endothelium-derived relaxant factors, extracellular calcium (Ca2+e) and muscarinic receptors were also evaluated as putative participants in the CRLI relaxant effect. CRLI relaxant effect was blocked by L-NAME, a nonselective inhibitor of nitric oxide synthase (NOS), and partially inhibited in a calcium-free solution (0Ca) and by atropine, but it remained unchanged in the presence of indomethacin and TEA. In summary, our data suggest interaction between CRLI and muscarinic receptors located in vascular endothelial cells leading to NOS activation triggered by a mechanism that involves Ca2+e along with the ability of CRLI to interact with heparan sulfate, a highly rated mechanoreceptor involved in eNOS activation. © 2014 Published by Elsevier Inc