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.

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 (Ca(2+)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 Ca(2+)e along with the ability of CRLI to interact with heparan sulfate, a highly rated mechanoreceptor involved in eNOS activation.

Teleangiectasia parafoveal: apresentaçäo de dois casos / Parafoveal telangectasis: report of two cases

Os autores apresentam o quadro clínico de dois casos de teleangiectasia parafoveolar, entidade de conhecimento recente ainda näo descrita em literatura de Língua Portuguesa. Säo apresentados os achados angiográficos e comentários quanto a possíveis diagnósticos diferenciais