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Wheat germ agglutinin inhibits thrombin‐induced rises in cytosolic free calcium and prostacyclin synthesis by human umbilical vein endothelial cells
Author(s) -
GrulichHenn Jürgen,
Weksler Babette B.,
Watanabe Kentaro,
Jaffe Eric A.
Publication year - 1988
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041370322
Subject(s) - wheat germ agglutinin , thrombin , umbilical vein , biochemistry , chemistry , agglutinin , prostacyclin , sialoglycoprotein , sialic acid , microbiology and biotechnology , biology , platelet , lectin , in vitro , immunology
Abstract To characterize the endothelial cell surface membrane glycoproteins that mediate thrombin stimulation of PGI 2 synthesis by human umbilical vein endothelial cells (HUVEC), HUVEC were stimulated with thrombin in the presence or absence of different lectins. Of the lectins tested, only wheat germ agglutinin (WGA) inhibited thrombin‐induced rises in cytosolic free calcium ([Ca 2+ ] i ), measured using Quin 2‐loaded HUVEC and PGI 2 production measured by radioimmunoassay. However, WGA by itself had no influence on baseline [Ca 2+ ] i or PGI 2 production and did not inhibit histamine‐induced rises in [Ca 2+ ] i . The inhibition of thrombin‐induced rises in [Ca 2+ ] i and PGI 2 production by WGA was dose dependent, with half‐maximal inhibition occurring at 2 μg/ml WGA also inhibited thrombin‐induced release of 3 H‐arachidonic acid. These effects of WGA were reversed by N‐acetyl‐glucosamine (GlcNAc) and N‐acetyl‐neuraminic acid, which bind specifically to WGA, but not by unrelated sugars. Succinylated WGA (succ‐WGA), a chemically modified derivative of WGA that binds to GlcNAc but, unlike native WGA, not to sialoglycoproteins, did not inhibit thrombin‐induced rises in [Ca 2+ ] i and PGI 2 production. These results suggest that thrombin induces rises in [Ca 2+ ] i and PGI 2 production by interacting with an endothelial surface membrane sialoglycoprotein.