Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA.
Laryngoscope. 2011 Sep;121(9):1929-34. doi: 10.1002/lary.21921. Epub 2011 Aug 16.
OBJECTIVES/HYPOTHESIS: Sinonasal respiratory epithelial mucociliary clearance is dependent on the transepithelial transport of ions such as Cl(-) . The objectives of the present study were to investigate the role of oxygen restriction in 1) Cl(-) transport across primary sinonasal epithelial monolayers, 2) expression of the apical Cl(-) channels cystic fibrosis transmembrane conductance regulator (CFTR) and transmembrane protein 16A (TMEM16A), and 3) the pathogenesis of chronic rhinosinusitis.
In vitro investigation.
Murine nasal septal epithelial (MNSE), wild type, and human sinonasal epithelial (HSNE) cultures were incubated under hypoxic conditions (1% O(2) , 5% CO(2) ). Cultures were mounted in Ussing chambers for ion transport measurements. CFTR and TMEM16A expression were measured using quantitative reverse-transcription polymerase chain reaction (RT-PCR).
The change in short-circuit current (ΔI(SC) in microamperes per square centimeter) attributable to CFTR (forskolin-stimulated) was significantly decreased due to a 12-hour hypoxia exposure in both MNSE (13.55 ± 0.46 vs. 19.23 ± 0.18) and HSNE (19.55 ± 0.56 vs. 25.49 ± 1.48 [control]; P < .05). TMEM16A (uridine triphosphate-stimulated transport) was inhibited by 48 hours of hypoxic exposure in MNSE (15.92 ± 2.87 vs. 51.44 ± 3.71 [control]; P < .05) and by 12 hours of hypoxic exposure in HSNE (16.75 ± 0.68 vs. 24.15 ± 1.35 [control]). Quantitative RT-PCR (reported as relative mRNA levels ± standard deviation) demonstrated significant reductions in both CFTR and TMEM16A mRNA expression in MNSE and HSNE owing to airway epithelial hypoxia.
Sinonasal epithelial CFTR and TMEM16A-mediated Cl(-) transport and mRNA expression were robustly decreased in an oxygen-restricted environment. These findings indicate that persistent hypoxia may lead to acquired defects in sinonasal Cl(-) transport in a fashion likely to confer mucociliary dysfunction in chronic rhinosinusitis.
目的/假设：鼻窦呼吸上皮的黏膜纤毛清除功能依赖于氯离子等离子的跨上皮转运。本研究的目的是探讨缺氧在以下方面的作用：1） 原代鼻窦上皮细胞单层的氯离子转运，2） 顶端氯离子通道囊性纤维化跨膜电导调节因子（CFTR）和跨膜蛋白 16A（TMEM16A）的表达，以及 3） 慢性鼻-鼻窦炎的发病机制。
体外研究。
用缺氧条件（1% O2，5% CO2）孵育鼠鼻隔上皮（MNSE）、野生型和人鼻窦上皮（HSNE）培养物。将培养物置于 Ussing 室中进行离子转运测量。用实时定量聚合酶链反应（RT-PCR）测量 CFTR 和 TMEM16A 的表达。
MNSE（13.55 ± 0.46 对 19.23 ± 0.18）和 HSNE（19.55 ± 0.56 对 25.49 ± 1.48 [对照]）中，CFTR（福司可林刺激）引起的短路电流（ΔIsc，以微安/平方厘米计）变化因 12 小时缺氧暴露而显著降低（P <.05）。MNSE 中，缺氧暴露 48 小时抑制 TMEM16A（三磷酸尿苷刺激转运）（15.92 ± 2.87 对 51.44 ± 3.71 [对照]；P <.05），HSNE 中，缺氧暴露 12 小时抑制 TMEM16A（16.75 ± 0.68 对 24.15 ± 1.35 [对照]）。实时 RT-PCR（以相对 mRNA 水平±标准差表示）表明，MNSE 和 HSNE 中的 CFTR 和 TMEM16A mRNA 表达均因气道上皮缺氧而显著降低。
鼻窦上皮 CFTR 和 TMEM16A 介导的氯离子转运和 mRNA 表达在缺氧受限的环境中显著减弱。这些发现表明，持续的缺氧可能导致鼻窦氯离子转运的获得性缺陷，从而导致慢性鼻-鼻窦炎的黏液纤毛功能障碍。
