Granzyme A and thrombin differentially promote the release of interleukin-8 from alveolar epithelial A549 cells
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Some of extracellular serine proteases with trypsin-like specificity of cleavage have been known to increase the release of inflammatory mediators from various cell types. For instance, two well-known trypsin-like serine proteases circulating in blood, granzyme A (GrA) and thrombin, have been found to promote interleukin (IL)-8 release from an alveolar epithelial A549 cell line. However, the mechanisms by which the proteases promote IL-8 release from the cells are not fully understood. In the present study, using A549 cells we found that (1) thrombin promoted IL-8 release from the cells via a mechanism partially involving activation of protease-activated receptor-1, a G-protein coupled receptor, whereas a recombinant form of GrA (rGrA) did it via a mechanism that does not involve the receptor activation; that (2) unlike rGrA, thrombin did not cause detachment and microtubule disruption of the cells; and that (3) the release of IL-8 induced by rGrA was inhibited in the presence of taxol, a microtubule-stabilizing reagent, whereas that induced by thrombin was not. These findings suggest that rGrA and thrombin promote the release of IL-8 from A549 cells through distinct mechanisms.
KeywordsA549 cells Granzyme A Interleukin-8 release Microtubule disruption Proteinase-activated receptor-1 Thrombin
N-α-benzyloxy l-lysine thiobenzyl ester
Recombinant form of rat GrA
Serum-free Dulbecco’s modified Eagle medium supplemented with 0.1% w/v BSA
This work was supported by Grants-in-Aid for Scientific Research (18580118 to S. Tsuzuki) from the Japan Society for the Promotion of Science.
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