Lectins are proteins that specifically bind to carbohydrates and form complexes with molecules and biological structures containing saccharides. The FRIL (Flt3 receptor interacting lectin) is a dimeric two-chain (αβ)2 lectin presenting 67kDa molecular mass. The interaction of FRIL with carbohydrates, as determined by molecular docking, showed that this lectin has highest affinity to the carbohydrate trimannoside (−135.618MDS), followed by trehalosamine (−127.072MDS) and αα-trehalose (−121.729MDS). FRIL evoked dose-dependent paw edema, increasing animal paw volumes. The edematogenic effect of FRIL was paralleled by an increase in vascular permeability, about 10-fold higher compared to control. FRIL also significantly raised the animals flinch reaction in the first, third and fifth hours in response to mechanical stimulation. Injection of α-methyl-d-mannoside associated with FRIL inhibited edema and hypernociception. The histopathological analysis of animal paws showed a characteristically acute inflammatory process that included severe infiltration of mixed leukocytes, changes in cytoarchitecture, edema and focal areas of hemorrhage. In addition, in silico assays confirmed that FRIL preferentially interacts with trimannoside that makes up the core N-glycans cell. Therefore, our study supports the hypothesis that the lectin domain and the likely glycoconjugates containing α-d-methyl mannoside residues contribute to the inflammatory effects of FRIL.
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