A C-type lectin from Bothrops jararacussu venom can adhere to extracellular matrix proteins and induce the rolling of leukocytes
L. Center of Biological and Health Sciences Laboratory of Animal Physiology) Elífio-Esposito, S.L. Center of Biological and Health Sciences Laboratory of Animal Physiology) Hess, P.N. Moreno, A.Lopes-Ferreira, M.A. O. Ricart, C.V. Souza, M.Center of Biological and Health Sciences Laboratory of Animal Physiology) Hasselman-Zielinski, F.A. Center of Biological and Health Sciences Laboratory of Animal Physiology) Becker, J.F. Center of Biological and Health Sciences Laboratory of Animal Physiology) Pereira, L.
Purification of a lectin from Bothrops jararacussu venom (BjcuL) was carried out using agarose-D-galactose affinity gel. MALDI-TOF gave a major signal at m/z 32028, suggesting the presence of a dimmer composed of two identical subunits. Divalent cations were required for the lectin activity, as complete absence of such ions reduced hemagglutination. BjcuL was more effective at neutral pH and showed total loss of activity at pH values below 4.0 and above 9.0. Its agglutinating activity remained stable at 25°C until 60min, but increased when at 35°C for at least 15min. Adhesion assays to extracellular matrix (ECM) glycoproteins showed that the biotinylated lectin (0.039-5.0µg/100µl) was capable of binding to fibronectin and vitronectin in a dose-dependent manner. The binding was partially inhibited in the presence of D-galactose. BjcuL (1.25-10µg/30µl) potential was investigated for leukocyte rolling and adhesion to endothelial cells in living microvessels using intravital microscopy, which showed that it induced a dose-dependent increase in rolling and adherence of leukocytes, acting directly on endothelial cells of postcapillary venules. The specific association between lectins and their ligands, either on the cell surface or on the ECM, is related to a variety of biological processes. The complementary characterization of BjcuL, shown here, is useful to further understand the venom effects and as a background for future investigation for therapeutic strategies.
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