International forum of allergy & rhinology · 2023
Hypoxia-induced cystic fibrosis transmembrane conductance regulator dysfunction is a universal mechanism underlying reduced mucociliary transport in sinusitis.
СтатьяПоддержка исследования: вне правительства СШАПоддержка NIH: внешняя программаНазвание и аннотация: Перевод пока не подготовлен
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Cho Do-Yeon, Zhang Shaoyan, Norwood T Graham, Skinner Daniel, Hollis Tonja A, Ehrhardt Marie L, Yang Lydia C, Lim Dong-Jin, Grayson Jessica W, Lazrak Ahmed, Matalon Sadis, Rowe Steven M, Woodworth Bradford A
Аннотация
INTRODUCTION: Hypoxia due to sinus obstruction is a major pathogenic mechanism leading to sinusitis. The objective of the current study is to define the electrophysiologic characteristics of hypoxia in vitro and in vivo.
METHODS: Cystic fibrosis bronchoepithelial cells expressing wild-type cystic fibrosis transmembrane conductance regulator (CFTR) and human sinonasal epithelial cells were exposed to 1% or atmospheric O2 for 24 h. Time-dependent production of cytoplasmic free radicals was measured. Cells were subjected to Ussing chamber and patch clamp technique where CFTR currents were recorded in whole-cell and cell-attached mode for single channel studies. Indices of mucociliary transport (MCT) were measured using micro-optical coherence tomography. In a rabbit hypoxic maxillary sinus model, tissue oxygenation, relative mRNA expression of HIF-1α, pH, sinus potential difference (SPD), and MCT were determined.
RESULTS: Ussing chamber (p < 0.05), whole-cell (p < 0.001), and single channel patch-clamp (p < 0.0001) showed significant inhibition of Cl- currents in hypoxic cells. Cytoplasmic free radicals showed time-dependent elevation peaking at 4 h (p < 0.0001). Airway surface liquid (p < 0.0001), periciliary liquid (p < 0.001), and MCT (p < 0.01) were diminished. Co-incubation with the free radical scavenger glutathione negated the impact of hypoxia on single channel currents and MCT markers. In sinusitis rabbits, mucosa exhibited low tissue oxygenation (p < 0.0001), increased HIF1α mRNA (p < 0.05), reduced pH (p < 0.01), and decreased MCT (p < 0.001). SPD measurements demonstrated markedly diminished transepithelial Cl- transport (p < 0.0001).
CONCLUSION: Hypoxia induces severe CFTR dysfunction via free radical production causing reduced MCT in vitro and in vivo. Improved oxygenation is critical to reducing the impact of persistent mucociliary dysfunction.
METHODS: Cystic fibrosis bronchoepithelial cells expressing wild-type cystic fibrosis transmembrane conductance regulator (CFTR) and human sinonasal epithelial cells were exposed to 1% or atmospheric O2 for 24 h. Time-dependent production of cytoplasmic free radicals was measured. Cells were subjected to Ussing chamber and patch clamp technique where CFTR currents were recorded in whole-cell and cell-attached mode for single channel studies. Indices of mucociliary transport (MCT) were measured using micro-optical coherence tomography. In a rabbit hypoxic maxillary sinus model, tissue oxygenation, relative mRNA expression of HIF-1α, pH, sinus potential difference (SPD), and MCT were determined.
RESULTS: Ussing chamber (p < 0.05), whole-cell (p < 0.001), and single channel patch-clamp (p < 0.0001) showed significant inhibition of Cl- currents in hypoxic cells. Cytoplasmic free radicals showed time-dependent elevation peaking at 4 h (p < 0.0001). Airway surface liquid (p < 0.0001), periciliary liquid (p < 0.001), and MCT (p < 0.01) were diminished. Co-incubation with the free radical scavenger glutathione negated the impact of hypoxia on single channel currents and MCT markers. In sinusitis rabbits, mucosa exhibited low tissue oxygenation (p < 0.0001), increased HIF1α mRNA (p < 0.05), reduced pH (p < 0.01), and decreased MCT (p < 0.001). SPD measurements demonstrated markedly diminished transepithelial Cl- transport (p < 0.0001).
CONCLUSION: Hypoxia induces severe CFTR dysfunction via free radical production causing reduced MCT in vitro and in vivo. Improved oxygenation is critical to reducing the impact of persistent mucociliary dysfunction.