Cystic Fibrosis/Pulmonary Research and Treatment Center, The University of North Carolina at Chapel Hill, 27599, USA.
Am J Respir Cell Mol Biol. 2011 Aug;45(2):253-60. doi: 10.1165/rcmb.2010-0253OC. Epub 2010 Oct 8.
Adenosine triphosphate (ATP) and its metabolite adenosine regulate airway mucociliary clearance via activation of purinoceptors. In this study, we investigated the contribution of goblet cells to airway epithelial ATP release. Primary human bronchial epithelial (HBE) cultures, typically dominated by ciliated cells, were induced to develop goblet cell metaplasia by infection with respiratory syncytial virus (RSV) or treatment with IL-13. Under resting conditions, goblet-cell metaplastic cultures displayed enhanced mucin secretion accompanied by increased rates of ATP release and mucosal surface adenosine accumulation as compared with nonmetaplastic control HBE cultures. Intracellular calcium chelation [1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester] or disruption of the secretory pathways (nocodazole, brefeldin A, and N-ethylmaleimide) decreased mucin secretion and ATP release in goblet-cell metaplastic HBE cultures. Conversely, stimuli that triggered calcium-regulated mucin secretion (e.g., ionomycin or UTP) increased luminal ATP release and adenyl purine accumulation in control and goblet-cell metaplastic HBE cultures. Goblet cell-associated ATP release was not blocked by the connexin/pannexin hemichannel inhibitor carbenoxolone, suggesting direct nucleotide release from goblet cell vesicles rather than the hemichannel insertion. Collectively, our data demonstrate that nucleotide release is increased by goblet cell metaplasia, reflecting, at least in part, a mechanism tightly associated with goblet cell mucin secretion. Increased goblet cell nucleotide release and resultant adenosine accumulation provide compensatory mechanisms to hydrate mucins by paracrine stimulation of ciliated cell ion and water secretion and maintain mucociliary clearance, and to modulate inflammatory responses.
三磷酸腺苷（ATP）及其代谢物腺苷通过激活嘌呤能受体来调节气道黏液纤毛清除功能。在这项研究中，我们研究了杯状细胞对气道上皮细胞 ATP 释放的贡献。原发性人支气管上皮（HBE）培养物通常以纤毛细胞为主，通过感染呼吸道合胞病毒（RSV）或用白细胞介素 13（IL-13）处理可诱导其发生杯状细胞化生。在静息状态下，与非化生对照 HBE 培养物相比，杯状细胞化生培养物显示出增强的粘蛋白分泌，伴随着更高的 ATP 释放率和黏膜表面腺苷积累。细胞内钙螯合[1,2-双（邻氨基苯氧基）乙烷-N,N,N',N'-四乙酸四乙酸四乙酰胺]或破坏分泌途径（诺考达唑、布雷菲德菌素 A 和 N-乙基马来酰亚胺）可减少杯状细胞化生 HBE 培养物中的粘蛋白分泌和 ATP 释放。相反，触发钙调节粘蛋白分泌的刺激物（例如，离子霉素或 UTP）增加了对照和杯状细胞化生 HBE 培养物中的腔 ATP 释放和腺嘌呤嘌呤积累。连接蛋白/连接蛋白半通道抑制剂 carbenoxolone 不能阻断杯状细胞相关的 ATP 释放，这表明核苷酸是从杯状细胞囊泡中直接释放出来的，而不是通过半通道插入。总之，我们的数据表明，杯状细胞化生会增加核苷酸的释放，这至少部分反映了一种与杯状细胞粘蛋白分泌紧密相关的机制。增加的杯状细胞核苷酸释放和由此产生的腺苷积累通过旁分泌刺激纤毛细胞离子和水分泌来提供水合粘蛋白的补偿机制，并维持黏液纤毛清除功能和调节炎症反应。
