Increased Production of LIGHT by T Cells in Eosinophilic Esophagitis Promotes Differentiation of Esophageal Fibroblasts Toward an Inflammatory Phenotype

Abstract

BACKGROUND & AIMS: Eosinophilic esophagitis (EoE) is an antigen-mediated eosinophilic disease of the esophagus that involves fibroblast activation and progression to fibrostenosis. Cytokines produced by T-helper type 2 cells and transforming growth factor beta 1 (TGFb1) contribute to the development of EoE, but other cytokines involved in pathogenesis are unknown. We investigate the effects of tumor necrosis factor superfamily member 14 (TNFSF14, also called LIGHT) on fibroblasts in EoE. METHODS: We analyzed publicly available esophageal CD3 þ Tcell single-cell sequencing data for expression of LIGHT. Esophageal tissues were obtained from pediatric patients with EoE or control individuals and analyzed by immunostaining. Human primary esophageal fibroblasts were isolated from esophageal biopsy samples of healthy donors or patients with active EoE. Fibroblasts were cultured; incubated with TGFb1 and/or LIGHT; and analyzed by RNA sequencing, flow cytometry, immunoblots, immunofluorescence, or reverse transcription polymerase chain reaction. Eosinophils were purified from peripheral blood of healthy donors, incubated with interleukin 5, cocultured with fibroblasts, and analyzed by immunohistochemistry. RESULTS: LIGHT was up-regulated in the esophageal tissues from patients with EoE, compared with control individuals, and expressed by several T-cell populations, including T-helper type 2 cells. TNF receptor superfamily member 14 (TNFRSF14, also called HVEM) and lymphotoxin beta receptor

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

“…T cells in EoE patients are also able to express the TNF-related cytokine LIGHT (TNF superfamily member 14), which can induce an inflammatory phenotype in fibroblasts ( Manresa et al, 2020 ).…”

LIGHT controls distinct homeostatic and inflammatory gene expression profiles in esophageal fibroblasts via differential HVEM and LTβR-mediated mechanisms

“…We have previously reported that LIGHT up-regulates a distinct subset of genes with inflammatory properties in esophageal fibroblasts (Fig. 1a ) 17 . In addition to its ability to up-regulate inflammatory mediators, an analysis of the LIGHT-repressed transcriptome revealed that LIGHT down-regulates multiple mediators of homeostatic functions including WNT factors (WNT5A, WNT2B), WNT receptors and targets (FZD4 and OLFM2), bone morphogenetic proteins (BMP6) or type 3 semaphorins (SEMA3, Fig.…”

“…TGF-β1 enhances HVEM expression on esophageal fibroblasts, and cells pretreated with TGF-β1 and stimulated with LIGHT display enhanced expression of genes such as IL-32 or ICAM-1 17 corresponding to the requirement for HVEM for modulating these molecules shown above. To further assess the isolated importance of HVEM, we overexpressed HVEM (HVEM-OE) in the presence of LTβR silencing (Fig.…”

“…LTβR is stably expressed in esophageal fibroblasts from different backgrounds, whereas HVEM expression can be increased by TGF-β1 17 . In line with this, an analysis of the transcript expression of these receptors in a previously published data set comparing normal esophagus to active EoE biopsies demonstrated that LTβR was more highly expressed than HVEM in normal biopsies (Fig.…”

“…We previously showed that a member of the tumor necrosis factor superfamily (TNFSF) of cytokines termed TNFSF14/LIGHT is produced in the esophagus during active EoE 17 . In vitro, LIGHT imposes an inflammatory phenotype on fibroblasts that closely resembles that described in the colon, expressing common markers such as ICAM-1, IL-32, IL-33 or CD74, among others 4 , 17 . LIGHT has gained momentum as a mediator of tissue remodeling that also induces inflammatory gene expression in lung fibroblasts and epithelial cells 18 – 20 .…”