Beppu Lisa Y, Anilkumar Arjun A, Newbury Robert O, Dohil Ranjan, Broide David H, Aceves Seema S
Division of Allergy and Immunology, University of California, San Diego, Calif; Department of Pediatrics, University of California, San Diego, Calif.
Division of Allergy and Immunology, University of California, San Diego, Calif; Department of Medicine, University of California, San Diego, Calif.
J Allergy Clin Immunol. 2014 Nov;134(5):1100-1107.e4. doi: 10.1016/j.jaci.2014.04.004. Epub 2014 May 13.
Eosinophilic esophagitis (EoE) is a chronic antigen-mediated disease characterized by esophageal eosinophilia, remodeling, and fibrosis. TGF-β1 is a central regulator of EoE remodeling and increases esophageal smooth muscle (ESM) cell contraction.
In this study we aimed to understand the molecular mechanisms by which TGF-β1 could induce ESM cell contraction.
We used primary human ESM cells and esophageal myofibroblasts (EMFs) to assess the mechanisms of TGF-β1-induced contraction. We analyzed the expression, phosphorylation, and function of phospholamban (PLN), a sarcoendoplasmic reticulum regulatory protein induced by TGF-β1. Expression of PLN, phospho-PLN, and its regulatory pathway was analyzed in the ESM of biopsy specimens from patients with EoE and control subjects. Gene silencing in EMFs from patients with EoE was used to understand the role of PLN in contraction.
TGF-β1 induced and phosphorylated PLN in primary human ESM cells and EMFs from patients with EoE. PLN and phospho-PLN levels were increased in smooth muscle from patients with EoE compared with that seen in smooth muscle from control subjects in vivo. PLN inhibition significantly diminished TGF-β1-induced EMF contraction in patients with EoE. PLN expression and ESM/EMF contraction depended on TGF-β receptor I signals.
We describe a previously unrecognized mechanism for ESM cell contraction that depends on TGF-β1, its receptors, and PLN. Because PLN levels are increased in smooth muscle from patients with EoE and PLN silencing diminishes contraction, we provide a novel potential mechanistic framework and therapeutic target for ESM dysfunction in patients with EoE.
嗜酸性粒细胞性食管炎（EoE）是一种慢性抗原介导的疾病，其特征为食管嗜酸性粒细胞增多、重塑和纤维化。转化生长因子-β1（TGF-β1）是EoE重塑的核心调节因子，可增加食管平滑肌（ESM）细胞收缩。
在本研究中，我们旨在了解TGF-β1诱导ESM细胞收缩的分子机制。
我们使用原代人ESM细胞和食管肌成纤维细胞（EMF）来评估TGF-β1诱导收缩的机制。我们分析了受TGF-β1诱导的肌浆网调节蛋白受磷蛋白（PLN）的表达、磷酸化及功能。对EoE患者和对照受试者活检标本的ESM中PLN、磷酸化PLN及其调节途径的表达进行了分析。采用基因沉默技术研究EoE患者EMF中PLN在收缩中的作用。
TGF-β1可诱导并磷酸化原代人ESM细胞及EoE患者的EMF中的PLN。与体内对照受试者的平滑肌相比，EoE患者平滑肌中的PLN和磷酸化PLN水平升高。抑制PLN可显著减弱EoE患者中TGF-β1诱导的EMF收缩。PLN的表达及ESM/EMF收缩依赖于TGF-β受体I信号。
我们描述了一种此前未被认识的ESM细胞收缩机制，该机制依赖于TGF-β1、其受体及PLN。由于EoE患者平滑肌中PLN水平升高，且PLN沉默可减弱收缩，我们为EoE患者ESM功能障碍提供了一个新的潜在机制框架和治疗靶点。
