Esophageal epithelial cells acquire functional characteristics of activated myofibroblasts after undergoing an epithelial to mesenchymal transition

Background and Aims: Eosinophilic esophagitis (EoE) is an allergic inflammatory disease that leads to esophageal fibrosis and stricture. We have recently shown that in EoE, esophageal epithelial cells undergo an epithelial to mesenchymal transition (EMT), characterized by gain of mesenchymal markers and loss of epithelial gene expression. Whether epithelial cells exposed to profibrotic cytokines can also acquire the functional characteristics of activated myofibroblasts, including migration, contraction, and extracellular matrix deposition, is relevant to our understanding and treatment of EoE-associated fibrogenesis. In the current study, we characterize cell migration, contraction, and collagen production by esophageal epithelial cells that have undergone cytokine-induced EMT in vitro. Methods and Results: Stimulation of human non-transformed immortalized esophageal epithelial cells (EPC2-hTERT) with profibrotic cytokines TNF alpha, TGF beta, and IL1 beta for three weeks led to acquisition of mesenchymal alpha SMA and vimentin, and loss of epithelial E-cadherin expression. Upon removal of the profibrotic stimulus, epithelial characteristics were partially rescued. TGF beta stimulation had a robust effect upon epithelial collagen production. Surprisingly, TNF alpha stimulation had the most potent effect upon cell migration and contraction, exceeding the effects of the prototypical profibrotic cytokine TGF beta. IL1 beta stimulation alone had minimal effect upon esophageal epithelial migration, contraction, and collagen production. Conclusions: Esophageal epithelial cells that have undergone EMT acquire functional characteristics of activated myofibroblasts in vitro. Profibrotic cytokines exert differential effects upon esophageal epithelial cells, underscoring complexities of fibrogenesis in EoE, and implicating esophageal epithelial cells as effector cells in EoE-associated fibrogenesis. (C) 2014 Published by Elsevier Inc.