A Unique Esophageal Extracellular Matrix Proteome Alters Normal Fibroblast Function in Severe Eosinophilic Esophagitis.

Abstract Background Eosinophilic esophagitis (EoE) is a chronic Th2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy but pro-fibrotic therapeutic targets are largely unclear. Objective To utilize proteomics and primary cell as a novel approach to determine relevant pro-fibrotic factors. Methods We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus opposing ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function. Results We cultured esophageal fibroblasts from normal or severe EoE esophagi on autologous versus opposing extracellular matrix (ECM). The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 (TSP-1) is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is significantly elevated in active EoE biopsies, and induces fibroblast collagen I production. Conclusion EoE fibroblasts secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. TSP-1 is a previously unappreciated pro-fibrotic molecule in EoE. Clinical Implications. The novel approach of culturing tissue fibroblasts on autologous versus opposing ECM has clinical utility for identifying previously unappreciated disease-specific druggable ECM targets in EoE and, potentially other, fibrotic disorders.