Stimulation of aquaporin-5 and transepithelial water permeability in human airway epithelium by hyperosmotic stress.
Research output: Contribution to journal › Journal article › Research › peer-review
Osmotic water permeability (P(f )) was measured in spheroid-shaped human nasal airway epithelial explants pre-exposed to increasing levels of hyperosmotic stress. The fluid-filled spheroids, derived from nasal polyps, were lined by a single cell layer with the ciliated apical cell membrane facing the outside. The P(f ) was determined from diameter changes of the spheroids in response to changes in bathing medium osmolarity forth and back between 300 and 225 mOsm x l(-1). Continuous diameter measurements also allowed determination of spontaneous fluid absorption. Hyperosmotic pretreatment (increase from 300 up to 600 mOsm x l(-1)) caused a time- and osmolarity-dependent increase (up to approximately 1.5 times) in epithelial P(f ) which was of similar magnitude in cystic fibrosis (CF) and non-CF spheroids. The effect saturated at approximately 450 mOsm x l(-1) and at approximately 24 h. Expression of aquaporin-5 (AQP5), studied by immunofluorescence and confocal microscopy, showed an increase in parallel with the increase in P(f ) following hyperosmotic stress. The AQP5 was localized both in cytoplasmic vesicles and in apical cell membranes. Spontaneous fluid absorption rates were equal in CF and non-CF spheroids and were not significantly influenced by hyperosmotic stress. The results suggest that hyperosmotic stress is an important activator of AQP-5 in human airway epithelium, leading to significantly increased transepithelial water permeability.
Original language | English |
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Journal | Pflügers Archiv: European Journal of Physiology |
Volume | 453 |
Issue number | 6 |
Pages (from-to) | 777-85 |
Number of pages | 8 |
ISSN | 0031-6768 |
DOIs | |
Publication status | Published - 2006 |
Bibliographical note
Keywords: Aquaporin 5; Cystic Fibrosis; Cytoplasmic Vesicles; Female; Fluorescent Antibody Technique; Humans; Hypertonic Solutions; Male; Nasal Mucosa; Nasal Polyps; Osmotic Pressure; Permeability; Spheroids, Cellular; Water
ID: 8419909