Camostat Attenuates Airway Epithelial Sodium Channel Function in Vivo through the Inhibition of a Channel-Activating Protease
Camostat Attenuates Airway Epithelial Sodium Channel Function in Vivo through the Inhibition of a Channel-Activating Protease
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DOI：
10.1124/jpet.108.148155
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发表时间：
2009-05-01
影响因子：
3.5
通讯作者：
Danahay, H.
中科院分区：
文献类型：
--
作者：
Coote, K.;Atherton-Watson, H. C.;Danahay, H.
抑制气道上皮钠通道（ENaC）功能可增强粘膜纤毛清除（MCC）。ENaC受通道激活蛋白酶（CAP）的正调控，因此预测CAP抑制剂对与受损MCC相关的疾病有益。本研究的目的是1）鉴定气道CAP的低分子量抑制剂和2）确定此类CAP抑制剂是否会转化为体内ENaC功能的负调节，从而增强MCC。为此，胰蛋白酶样蛋白酶抑制剂卡莫司他在人气道上皮细胞模型中提供了有效的（IC 50类似于50 nM）和延长的ENaC功能衰减，这在添加过量胰蛋白酶时是可逆的。在原代人支气管上皮细胞中，胎盘bikunin >卡莫司他> 4-胍基苯甲酸4-羧甲基-苯基酯>抑肽酶>>大豆胰蛋白酶抑制剂= α 1-抗胰蛋白酶的效力顺序与对前列腺素（气道CAP的分子候选物）的抑制所观察到的基本一致.在体内，局部气道给予卡莫司他诱导豚鼠气管中ENaC活性的有效和长期衰减（ED 50 = 3 μ g/kg）。当在清醒绵羊中通过雾化吸入给药时，卡莫司他在吸入给药后至少5小时增强MCC。总之，卡莫司他减弱ENaC功能并增强MCC，为这种方法提供了治疗上测试ENaC功能负调节的机会。
Inhibition of airway epithelial sodium channel ( ENaC) function enhances mucociliary clearance (MCC). ENaC is positively regulated by channel-activating proteases (CAPs), and CAP inhibitors are therefore predicted to be beneficial in diseases associated with impaired MCC. The aims of the present study were to 1) identify low-molecular-weight inhibitors of airway CAPs and 2) to establish whether such CAP inhibitors would translate into a negative regulation of ENaC function in vivo, with a consequent enhancement of MCC. To this end, camostat, a trypsin-like protease inhibitor, provided a potent (IC50 similar to 50 nM) and prolonged attenuation of ENaC function in human airway epithelial cell models that was reversible upon the addition of excess trypsin. In primary human bronchial epithelial cells, a potency order of placental bikunin > camostat > 4-guanidinobenzoic acid 4-carboxymethyl- phenyl ester > aprotinin >> soybean trypsin inhibitor = alpha 1-antitrypsin, was largely consistent with that observed for inhibition of prostasin, a molecular candidate for the airway CAP. In vivo, topical airway administration of camostat induced a potent and prolonged attenuation of ENaC activity in the guinea pig trachea (ED50 = 3 mu g/kg). When administered by aerosol inhalation in conscious sheep, camostat enhanced MCC out to at least 5 h after inhaled dosing. In summary, camostat attenuates ENaC function and enhances MCC, providing an opportunity for this approach toward the negative regulation of ENaC function to be tested therapeutically.