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Chitosan‐induced phospholipase A 2 activation and arachidonic acid mobilization in P388D 1 macrophages
Author(s) -
Bianco Ismael D.,
Balsinde Jesús,
Beltramo Dante M.,
Castagna Leonardo F.,
Landa Carlos A.,
Dennis Edward A.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01089-9
Subject(s) - arachidonic acid , chitosan , phospholipase a2 , lipopolysaccharide , chemistry , phospholipase , phospholipase a , microbiology and biotechnology , cytosol , macrophage , mobilization , biochemistry , biology , immunology , enzyme , in vitro , history , archaeology
We have found that chitosan, a polysaccharide present in fungal cell walls, is able to activate macrophages for enhanced mobilization of arachidonic acid in a dose‐ and time‐dependent manner. Studies aimed at identifying the intracellular effector(s) implicated in chitosan‐induced arachidonate release revealed the involvement of the cytosolic Group IV phospholipase A 2 (PLA 2 ), as judged by the inhibitory effect of methyl arachidonoyl fluorophosphonate but not of bromoenol lactone. Interestingly, priming of the macrophages with lipopolysaccharide renders the cells more sensitive to a subsequent stimulation with chitosan, and this enhancement is totally blocked by the secretory PLA 2 inhibitor 3‐(3‐acetamide)‐1‐benzyl‐2‐ethylindolyl‐5‐oxy‐propanesulfonic acid (LY311727). Collectively, the results of this work establish chitosan as a novel macrophage‐activating factor that elicits AA mobilization in P388D 1 macrophages by a mechanism involving the participation of two distinct phospholipases A 2 .