Center for Gastrointestinal Biology and Disease, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.
Division of Gastroenterology, Department of Medicine, Duke University, Durham, North Carolina.
Am J Physiol Gastrointest Liver Physiol. 2020 Apr 1;318(4):G613-G623. doi: 10.1152/ajpgi.00086.2019. Epub 2020 Feb 18.
Esophageal injury from acid exposure related to gastroesophageal reflux disease is a common problem and a risk factor for development of Barrett's esophagus and esophageal adenocarcinoma. Our previous work highlights the benefits of using porcine esophagus to study human esophageal disease because of the similarities between porcine and human esophagus. In particular, esophageal submucosal glands (ESMGs) are present in human esophagus and proximal porcine esophagus but not in rodent esophagus. Although CFTR is expressed in the ducts of ESMGs, very little is known about CFTR and alternate anion channels, including ClC-2, in the setting of acid-related esophageal injury. After finding evidence of CFTR and ClC-2 in the basal layers of the squamous epithelium, and in the ducts of the ESMGs, we developed an ex vivo porcine model of esophageal acid injury. In this model, esophageal tissue was placed in Ussing chambers to determine the effect of pretreatment with the ClC-2 agonist lubiprostone on tissue damage related to acid exposure. Pretreatment with lubiprostone significantly reduced the level of acid injury and significantly augmented the recovery of the injured tissue ( < 0.05). Evaluation of the interepithelial tight junctions showed well-defined membrane localization of occludin in lubiprostone-treated injured tissues. Pretreatment of tissues with the Na-K-2Cl cotransporter inhibitor bumetanide blocked lubiprostone-induced increases in short-circuit current and inhibited the reparative effect of lubiprostone. Furthermore, inhibition of ClC-2 with ZnCl blocked the effects of lubiprostone. We conclude that ClC-2 contributes to esophageal protection from acid exposure, potentially offering a new therapeutic target. This research is the first to describe the presence of anion channels ClC-2 and CFTR localized to the basal epithelia of porcine esophageal mucosa and the esophageal submucosal glands. In the setting of ex vivo acid exposure, the ClC-2 agonist lubiprostone reduced acid-related injury and enhanced recovery of the epithelial barrier. This work may ultimately provide an alternate mechanism for treating gastroesophageal reflux disease.
胃酸相关的食管损伤与胃食管反流病有关，是一种常见问题，也是发展成 Barrett 食管和食管腺癌的危险因素。我们之前的工作强调了使用猪食管研究人类食管疾病的益处，因为猪和人食管之间有很多相似之处。特别是，食管黏膜下腺（ESMGs）存在于人类食管和近端猪食管中，但不存在于啮齿动物食管中。尽管 CFTR 表达在 ESMGs 的导管中，但对于 CFTR 和替代阴离子通道，包括 ClC-2，在胃酸相关的食管损伤中，人们知之甚少。在发现 CFTR 和 ClC-2 存在于鳞状上皮的基底层和 ESMGs 的导管中后，我们建立了一种猪食管酸损伤的离体模型。在该模型中，将食管组织置于 Ussing 室中，以确定 ClC-2 激动剂鲁比前列酮预处理对酸暴露相关组织损伤的影响。鲁比前列酮预处理显著降低了酸损伤的程度，并显著增强了受损组织的恢复（<0.05）。对细胞间紧密连接的评估显示，在鲁比前列酮处理的受损组织中，occludin 的膜定位清晰。用 Na-K-2Cl 共转运体抑制剂布美他尼预处理组织可阻断鲁比前列酮诱导的短路电流增加，并抑制鲁比前列酮的修复作用。此外，用 ZnCl2 抑制 ClC-2 可阻断鲁比前列酮的作用。我们得出结论，ClC-2 有助于食管免受胃酸暴露的影响，可能提供新的治疗靶点。这项研究首次描述了阴离子通道 ClC-2 和 CFTR 定位于猪食管黏膜和食管黏膜下腺的基底上皮。在离体酸暴露的情况下，ClC-2 激动剂鲁比前列酮可减少与酸相关的损伤，并增强上皮屏障的恢复。这项工作最终可能为治疗胃食管反流病提供一种替代机制。
