Modulation of Ca2+ influx by a mediator released from human tracheal epithelial cells exposed to ozone in vitro.
Intracellular free Ca2+ ([Ca2+]i) plays a vital role both in maintaining normal cellular function and in cell killing. Few studies have been published regarding its role in ozone (O3)-induced health effects. This study investigated the effect and mechanism of O3 exposure on [Ca2+]i in human tracheal epithelial (HTE) cells. HTE cells grown on Costar Transwell inserts with a liquid-gas interface were exposed to 0, 0.05, 0.1, 0.2 and 0.4 ppm O3 at 37 degrees C for 1 h. After exposure, [Ca2+]i was measured using the fluorescent dye Fluo 3. O3 at 0.4 ppm produced a significant increase in [Ca2+]i, and the increases in [Ca2+]i were blocked by verapamil and 8-(diethylamino)-octyl-3,4,5,-trimethoxybenzoate (TMB-8). These results suggest that the O3-induced [Ca2+]i elevation may involve both Ca2+ release from internal stores and Ca2+ influx across the plasma membrane. Furthermore, both buffer and cell lysate of HTE cells exposed to 0.4 ppm O3 caused a rapid increase in [Ca2+]i of THP-1 human phagocytic monocytes, but the buffer and lysate from air exposed cells did not. These results suggest that O3 exposure causes HTE cells to release a diffusible mediator from the empty Ca(2+)-storing organelle and may be responsible for the sustained and persistent [Ca2+]i elevation in HTE cells exposed to 0.4 ppm O3.
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Institute of Environmental Medicine, New York University Medical Center, Tuxedo 10987, USA.
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D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism; D009994:Osmolar Concentration; D010126:Ozone / Q000494:pharmacology*; D010586:Phagocytes / Q000378:metabolism; D014132:Trachea / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D018836:Inflammation Mediators; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D010126:Ozone; D014700:Verapamil; D002118:Calcium