Effect of signaling inhibitors on the release of lysozyme from human neutrophils activated by Sambucus nigra agglutinin.
The effect of alpha-NeuAc(2-->6)Gal/GalNAc-specific lectin from Sambucus nigra (SNA) on the release of lysozyme from human neutrophils was studied in vitro. Interaction of cells with the lectin was accompanied by dose-dependent release of lysozyme, which was increased in the presence of cytochalasin B. The involvement of intracellular signaling pathways in the lectin-induced degranulation of neutrophils was determined using a panel of specific inhibitors tested at concentrations in the range of 10-100 microM. Aristolochic acid (a phospholipase A2 inhibitor), indomethacin (a cyclooxygenase inhibitor), neomycin sulfate (a phospholipase C inhibitor), trifluoperazine (a calmodulin antagonist/protein kinase C inhibitor), N-ethylmaleimide (a sulfhydryl reagent), and guanosine-5;-O-(2-thiodiphosphate) (a G-protein inhibitor) were found to reduce SNA-induced lysozyme release from neutrophils by 20-45%. The treatment of cells with bisindolylmaleimide (a protein kinase C inhibitor), H-8 (an inhibitor of protein kinases A, C, G and of myosin light chain kinase), PD 98059 (a MAP kinase inhibitor), and (+/-)-methoxyverapamil (a Ca2+-channel blocker) failed to affect the release of lysozyme. These results indicate that only selective intracellular pathways associated with activation of G-proteins and phospholipid metabolism as well as the thiol-dependent signaling systems are apparently involved in the realization of the SNA-induced degranulation response of human neutrophils.
Gorudko
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IV
Department of Biophysics, Belarusian State University, Minsk, 220050, Belarus. gorudko@phys.bsu.unibel.by
Timoshenko
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AV
D015550:Cell Degranulation / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D037102:Lectins / Q000494:pharmacology*; D009113:Muramidase / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D037121:Plant Lectins; D054788:Ribosome Inactivating Proteins; D015398:Signal Transduction / Q000187:drug effects
D037102:Lectins; D037121:Plant Lectins; C050600:Sambucus nigra lectins; D009113:Muramidase; D054788:Ribosome Inactivating Proteins