Structural analysis of Dioclea lasiocatpa lectin : a C6 cells apoptosis-inducing protein

Lectins are multidomain proteins that specifically recognize various carbohydrates. The structural characterization of these molecules is crucial in understanding their function and activity in systems and organisms. Most cancer cells exhibit changes in glycosylation patterns, and lectins may be able to recognize these changes. In this work, Dioclea lasiocarpa seed lectin (DLL) was structurally characterized. The lectin presented a high degree of similarity with other lectins isolated from legumes, presenting a jelly roll motif and a metal-binding site stabilizing the carbohydrate-recognition domain. DLL demonstrated differential interactions with carbohydrates, depending on type of glycosidic linkage present in ligands. As observed by the reduction of cell viability in C6 cells, DLL showed strong antiglioma activity by mechanisms involving activation of caspase 3

Vatairea guianensis lectin stimulates changes in gene expression and release of TNF‐α from rat peritoneal macrophages via glycoconjugate binding

Using a rat model of peritonitis, we herein report the inflammatory effect induced by the lectin isolated from Vatairea guianensis (VGL) seeds in the context of interactions between VGL and both toll-like receptor 4 (TLR4) and tumor necrosis factor receptor 1 (TNFR1). Peritoneal macrophages were stimulated with VGL for dose-dependent gene expression and release of TNF-alpha. In vivo results showed that VGL (1 mg/kg; intraperitoneal) induced peritonitis in female Wistar rats. Leukocyte migration, macrophage activation, and protein leakage were measured 3 and 6 hours after induction. In vitro, peritoneal macrophages were stimulated with VGL for gene expression and TNF-alpha dosage (mean +/- SEM (n = 6), analysis of variance, and Bonferroni's test (P < .05)). In silico, VGL structure was applied in molecular docking with representative glycans. It was found that (a) VGL increases vascular permeability and stimulates leukocyte migration, both rolling and adhesion; (b) lectin-induced neutrophil migration occurs via macrophage stimulation, both in vitro and in vivo; (c) lectin interacts with TLR4 and TNFR1; and (d) stimulates TNF-alpha gene expression (RT-PCR) and release from peritoneal macrophages. Thus, upon lectin-glycan binding on the cell surface, our results suggest that VGL induces an acute inflammatory response, in turn activating the release of peritoneal macrophages via TNF-alpha and TLR and/or TNFR receptor pathways