ANTIPROTEASES ATTENUATE THE RELEASE OF NEUTROPHIL CHEMOTACTIC ACTIVITY FROM BRONCHIAL EPITHELIAL-CELLS INDUCED BY SMOKE

The released neutrophil chemotactic activity (NCA)from bronchial epith elial cells (BECs) in response to smoke extract was evaluated by rever se-phase, high-performance liquid chromatography (RP-HPLC) and the inv olvement of proteolytic activity was assessed for the release of NCA f rom BECs. Smoke extract stimulated the release of NCA (55.3 +/- 5.2 vs . 17.3 +/- 4.1 cells per high-power field [HPF], p<.001) The released activity determined by RP-HPLC analysis was 15-hydroxyeicosatetraenoic acid and leukotriene B-4. Several structurally and functionally diffe rent serine protease inhibitors, including alpha-1-protease inhibitor (alpha-1-PI), chloromethyl ketone (CK) derivatives, N-tosyl-L-lysine C K (TLCK), methoxysuccinyl-Ala-Ala-Pro-Val CK (SPCK), N-alpha-tosyl-L-p henylalanine CK (TPCK), and N-alpha-p-tosyl-L-arginine methyl ester hy drochloride (TAME), attenuated the release of NCA (p<.01) in, a dose-d ependent fashion. Leupeptin, a cysteine protease inhibitor, has only a small effect on the release of NCA (p<.05), and phosphoramidon, a neu tral endopeptidase inhibitor, had no effect. The measurement of proteo lytic enzyme activity wing synthetic substrate S-2288 revealed that sm oke extract significantly (p<.05) augmented the serine protease activi ty in BEC layers. Culture supernatant fluids and cell lysates of BECs in response to smoke extract solubilized C-14-labeled casein. These re sults suggest that BECs may release lipoxygenase-derived NCA in respon se to smoke extract and that the release of NCA may involve the activa tion of proteolytic activity of BECs which was inhibited by serine pro tease inhibitors.