Burnett School of Biomedical Sciences, University of Central Florida, 4110 Libra Dr., BMS, Building 20, rm 223, Orlando, FL 32816, United States.
Burnett School of Biomedical Sciences, University of Central Florida, 4110 Libra Dr., BMS, Building 20, rm 223, Orlando, FL 32816, United States.
Cytokine. 2019 Nov;123:154782. doi: 10.1016/j.cyto.2019.154782. Epub 2019 Jul 29.
Reflux esophagitis is a result of esophageal exposure to acid and bile during episodes of gastroesophageal reflux. Aside from chemical injury to the esophageal epithelium, it has been shown that acid and bile induce cytokine-mediated injury by stimulating the release of pro-inflammatory cytokines. During the repair and healing process following reflux injury, the squamous esophageal cells are replaced with a columnar epithelium causing Barrett's metaplasia, which predisposes patients to esophageal adenocarcinoma. We identified a novel player in gastroesophageal reflux injury, the TGFβ family member Activin A (ActA), which is a known regulator of inflammation and tissue repair. In this study, we show that in response to bile salt and acidified media (pH 4) exposure, emulating the milieu to which the distal esophagus is exposed during gastroesophageal reflux, long-term treated, tolerant esophageal keratinocytes exhibit increased ActA secretion and a pro-inflammatory cytokine signature. Furthermore, we noted increased motility and expression of the stem cell markers SOX9, LGR5 and DCLK1 supporting the notion that repair mechanisms were activated in the bile salt/acid-tolerant keratinocytes. Additionally, these experiments demonstrated that de-differentiation as characterized by the induction of YAP1, FOXO3 and KRT17 was altered by ActA/TGFβ signaling. Collectively, our results suggest a pivotal role for ActA in the inflammatory GERD environment by modulating esophageal tissue repair and de-differentiation.
反流性食管炎是由于胃食管反流期间食管暴露于胃酸和胆汁引起的。除了对食管上皮的化学损伤外,研究还表明,酸和胆汁通过刺激促炎细胞因子的释放来诱导细胞因子介导的损伤。在反流损伤后的修复和愈合过程中,鳞状食管细胞被柱状上皮取代,导致巴雷特化生,使患者易患食管腺癌。我们发现了一种新的胃食管反流损伤因子,即 TGFβ 家族成员激活素 A(ActA),它是炎症和组织修复的已知调节剂。在这项研究中,我们表明,在响应胆汁盐和酸化介质(pH4)暴露时,模拟胃食管反流期间远端食管暴露的环境,长期耐受处理的食管角质形成细胞表现出增加的 ActA 分泌和促炎细胞因子特征。此外,我们注意到运动性增加和干细胞标志物 SOX9、LGR5 和 DCLK1 的表达增加,支持修复机制在胆汁盐/酸耐受角质形成细胞中被激活的观点。此外,这些实验表明,ActA/TGFβ 信号转导改变了由 YAP1、FOXO3 和 KRT17 诱导的去分化特征。综上所述,我们的研究结果表明,ActA 在炎症性 GERD 环境中通过调节食管组织修复和去分化起着关键作用。
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