Eosinophilic Esophagitis Drives Tissue Fibroblast Regenerative Programs Towards Pathologic Dysfunction

Background: Pathologic tissue remodeling with scarring and tissue rigidity has been demonstrated in inflammatory, autoimmune, and allergic diseases. Eosinophilic esophagitis (EoE) is an allergic disease that is diagnosed and managed by repeated biopsy procurement, allowing an understanding of tissue fibroblast dysfunction. While EoE associated tissue remodeling causes clinical dysphagia, food impactions and esophageal rigidity and strictures, molecular mechanisms driving these complications remain under investigation.

Objective: We hypothesized that chronic EoE inflammation induces pathogenic fibroblasts with dysfunctional tissue regeneration and motility.

Methods: We used single cell RNA sequence (scRNA-Seq), fluorescence activated cell sorting analysis, and fibroblast differentiation and migration assays to decipher the induced and retained pathogenic dysfunctions in EoE versus healthy esophageal fibroblasts.

Results: Differentiation assays demonstrated that active EoE fibroblasts retain regenerative programs for rigid cells such as chondrocytes (p<0.05) but lose healthy fibroblast capacity for soft cells such as adipocytes (p<0.01) which was reflected in biopsy immunostaining (p<0.01). EoE, but not healthy, fibroblasts have pro-inflammatory and pro-rigidity transcriptional programs on scRNA-Seq. In vivo, regenerative fibroblasts reside in perivascular regions and near the epithelial junction and, during EoE, have significantly increased migration (p<0.01). Flow analysis and functional assays demonstrated that regenerative EoE fibroblasts have decreased surface CD73 expression and activity (both p<0.05) compared to healthy, indicating aberrant ATP handling. EoE fibroblast dysfunctions were induced in healthy fibroblasts by reducing CD73 activity and rescued in EoE using adenosine repletion.

Conclusion: A normalization of perturbed extracellular ATP handling and CD73 could improve pathogenic fibroblast dysfunction and tissue regeneration in type 2 inflammatory diseases.