Maintaining pulmonary alveolar lining fluid ionic balance is crucial for proper gas exchange. Our previous research investigated ozone (O3), a major respiratory pollutant, effects on K+ current (IK) in human lung epithelial cells (A549 cell line). O3 exposure significantly impaired K+ flow, diminishing the outward rectifier part of the current. This effect is indirect, mediated by O3 by-products, primarily 4-hydroxy-nonenal (4-HNE) and hydrogen peroxide (H2O2). This study examined the impact of 4-HNE and H2O2 on IK in human lung cells and assessed protective function of catalase. A549 cells were exposed to O3 (0.1 ppm, 30’), 4-HNE (5-20 μM, 30’), exogen H2O2 (20 μM, 30’) or glucose oxidase (GO; 10 mU/l, 1h) used to generate intracellular H2O2, and analyzed after 24h. Catalase (1000U, 1.5h pre-incubation) was used for protection assays. Western blot, immunofluorescence, and patch-clamp techniques were employed to investigate by-product effects on IK. 4-HNE reduced IK, although less potently than O3. Endogenously generated H2O2 via GO fully mimicked the effect of O3 expoure. Catalase effectively restored the O3-suppressed outward rectifier current to control levels. These findings indicate that 4-HNE and H2O2 mediate the effects of O3 on potassium channels. The protective action of catalase underscores O3 by-product-induced disruption of cellular redox balance. Future research will explore their interplay and the activated biomolecular pathways.
Ozone and lung epithelium: dissecting the mechanism of potassium current modulation
Rita Canella
;M. Benedusi;G. Trinchera;A. Pignatelli;G. Valacchi
2025
Abstract
Maintaining pulmonary alveolar lining fluid ionic balance is crucial for proper gas exchange. Our previous research investigated ozone (O3), a major respiratory pollutant, effects on K+ current (IK) in human lung epithelial cells (A549 cell line). O3 exposure significantly impaired K+ flow, diminishing the outward rectifier part of the current. This effect is indirect, mediated by O3 by-products, primarily 4-hydroxy-nonenal (4-HNE) and hydrogen peroxide (H2O2). This study examined the impact of 4-HNE and H2O2 on IK in human lung cells and assessed protective function of catalase. A549 cells were exposed to O3 (0.1 ppm, 30’), 4-HNE (5-20 μM, 30’), exogen H2O2 (20 μM, 30’) or glucose oxidase (GO; 10 mU/l, 1h) used to generate intracellular H2O2, and analyzed after 24h. Catalase (1000U, 1.5h pre-incubation) was used for protection assays. Western blot, immunofluorescence, and patch-clamp techniques were employed to investigate by-product effects on IK. 4-HNE reduced IK, although less potently than O3. Endogenously generated H2O2 via GO fully mimicked the effect of O3 expoure. Catalase effectively restored the O3-suppressed outward rectifier current to control levels. These findings indicate that 4-HNE and H2O2 mediate the effects of O3 on potassium channels. The protective action of catalase underscores O3 by-product-induced disruption of cellular redox balance. Future research will explore their interplay and the activated biomolecular pathways.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
