Defining the impact of type 1 cytokine signaling on STAT-mediated epithelial reprogramming and barrier dysfunction in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory condition of the esophagus triggered by an immune response to food antigens. Despite effective treatment that leads to histologic remission, there are persistent changes in mucosal gene expression, epithelial differentiation, and histologic anomalies, including basal cell hyperplasia. Recent findings from other tissue sites indicate that mucosal inflammation can induce chromatin remodeling via immune signaling, including the JAK/STAT pathway. However, the mechanisms governing chromatin remodeling and persistent remodeling in the esophagus remain unknown. IL-4/IL-13 signaling via signal transducer and activator of transcription 6 (STAT6) has been shown to cause epithelial barrier dysfunction in EoE. However, emerging data suggests that other STATs may be involved in EoE. These include STAT3, which is also downstream of the type II IL-4 receptor, and STAT1. We have recently shown there is upregulation of interferon signature genes in the esophageal epithelium during EoE, indicating that there is dysregulation of multiple STAT pathways within the epithelium during EoE. Here, we will examine the specific roles of STAT3 and STAT1 in regulating STAT6-driven epithelial barrier function. We will determine the extent to which (1) coordinate activation of STAT1 via IFN-g will antagonize STAT3 and STAT6-mediated effects, and (2) coordinate activation of STAT3 and STAT6 will have synergistic effects. We generate human epithelial knockout lines (STAT1KO, STAT3 KO) using CRISPR-Cas9 and will interrogate the specific interactions of STAT1 and STAT3 on STAT6-mediated gene expression, chromatin remodeling, and epithelial barrier dysfunction. We will create novel epithelial conditional STAT1 and STAT3 knockout mice to evaluate the respective role of each transcription factor within the complex inflammatory milieu of EoE. The proposed experiments will advance understanding of the crosstalk between T1 and T2 cytokine signaling and epithelium in the esophagus. We will examine regulatory networks that impact JAK/STAT signaling within the epithelium and tissue-specific transcription factor behavior and its impact on chromatin remodeling. This work will identify key molecular drivers of persistent symptoms, paving the way for novel therapies for patients with esophageal remodeling and persistent symptoms. By addressing mechanisms that lead to chronic tissue remodeling and dysfunction, this study could ultimately improve long- term health outcomes for EoE patients, contributing to the goal of enhancing the quality of life for those with immune-mediated diseases. Project Number: 1R01AI184785-01A1 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Allergy and Infectious Diseases (NIAID) | Principal Investigator: Melanie Ruffner | Institution: CHILDREN'S HOSP OF PHILADELPHIA, PHILADELPHIA, PA | Award Amount: $3,375,359 | Activity Code: R01 | Study Section: Digestive and Nutrient Physiology and Diseases Study Section [DNPD] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R01AI18478501A1