ABSTRACT: Eosinophilic esophagitis (EoE) is a T helper type 2 (TH2) cytokine-associated disease charaterized by eosinophil infiltration, epithelial cell hyperplasia and tissue remodeling. Recent studies have highlighted a major contribution for IL-13 in EoE pathogenesis. Paired immunoglobulin-like receptor (PIR)-B is a cell surface immune-inhibitory receptor that is expressed by eosinophils and postulated to regulate eosinophil development and migration. We report that Pirb is upregulated in the esophagus after inducible overexpression of IL-13 (CC10-IL13 Tg mice) and is overexpressed by esophageal eosinophils. CC10-IL13Tg/PirB-/- mice displayed increased esophageal eosinophilia and EoE pahtology, including epithelial cell thickening, fibrosis and angiogenesis, compared with CC10-IL13 Tg/PirB+/+ mice. Transcriptome analysis of primary Pirb+/+ and Prib-/- esophageal eosinophils revealed increased expression of transcripts associated with promoting tissue remodeling in Pirb-/- eosinophils including pro-fibrotic genes, genes promoting epithelial-to-mesenchymal transition (EMT) and genes associated with epithelial growth. These data identify PIR-B as a molecular checkpoint in IL-13-induced eosinophil accumulation and activation, which may serve as a novel target for future therapy in EoE.
Project description:Distinct subsets of eosinophils are reported in inflammatory and healthy tissues, yet the functions of uniquely specialized eosinophils and the signals that elicit them, particularly in eosinophilic esophagitis (EoE), are not well understood. Herein, we report an ex-vivo system wherein freshly isolated human eosinophils were cocultured with esophageal epithelial cells and disease-relevant pro-inflammatory (IL-13) or pro-fibrotic (TGF-β) cytokines. Our results demonstrate that disease-relevant pro-inflammatory and pro-fibrotic signals present in the esophagus of EoE patients cause distinct profiles of eosinophil activation and gene expression.
Project description:During food trigger reintroductions, eosinophilia can recur in a patchy manner both endoscopically and histologically. We postulated that areas containing low eosinophils represented the early stage of EoE recurrence, while areas with >15 eos/HPF represented established active EoE. We identified ten patients with prior pan-esophageal EoE who experienced patchy eosinophilia during trigger food reintroduction. The progression of recurrent EoE is illustrated by the transcriptional changes occurring from baseline remission through recurrent low and high eosinophil tissues in those with paired time points. We identified novel genes of cytokine regulation distinct to the low eosinophil tissue, indicating involvement of such cytokines before the onset of diagnostic eosinophilic infiltration. The advancement to robust eosinophil is associated with more severe epithelial injury in conjunction with further inflammation. Utilization of a food antigen re-exposure model elucidates immunological and epithelial changes that instigate and perpetuate the development of EoE.
Project description:Eosinophilic esophagitis (EoE) is a chronic immune-mediated disorder triggered by specific food antigens, characterized by eosinophil-rich multicellular inflammation and structural changes in the epithelium. Treatment options for EoE include dietary therapy, pharmacological therapy, or a combination of both, chosen based on the patient's preference and clinical progression. Pharmacological options include proton pump inhibitors (PPIs), corticosteroids, and biologic therapy. Although PPI therapy is used for EoE management, its underlying mechanism of action remains unclear. To investigate the effects of omeprazole, an orally bioavailable PPI commonly used for EoE therapy, on the dynamics of esophageal epithelial barrier function and inflammation, we employed air-liquid interface (ALI) culture. We examined how omeprazole affects gene expression changes caused by IL-13 treatment. ALI cultures were treated with 100 ng/ml of IL-13 and/or 50 µM of acid-activated omeprazole for 96 hours, and bulk RNA sequencing was performed to analyze the epithelial-specific transcriptomes of IL-13 and/or omeprazole-treated ALI. Our findings suggest potential gene interactions where omeprazole may mitigate transcriptional changes induced by IL-13, indicating that omeprazole may attenuate IL-13 mediated epithelial dysfunction relevant to EoE pathophysiology by modulating pathways associated with inflammation, tissue repair, and cell-cell communication.
Project description:Introduction Disruption of the epithelial barrier can induce eosinophilic esophagitis (EoE), a TH2-mediated food- and aeroallergen associated chronic inflammatory disease 1, 2. The expression of IL-20 subfamily cytokines, IL-19, IL-20 and IL-24, is increased in TH2-mediated diseases, yet their function in EoE is unknown. Methods Combining RNA-sequencing (RNA-seq) and proteome analysis, we have examined the effects of the IL-20 subfamily on esophageal epithelial cells using patient-derived organoids and an experimental EoE mouse model. Results When stimulated with IL-20 subfamily cytokines patient-derived esophageal organoids showed decreased expression of Filaggrin (FLG) and Filaggrin 2 (FLG2) responsible for epithelial cornification. In agreement, EoE patients with active inflammation showed elevated IL-20 subfamily cytokines and decreased FLG and FLG2 expression. Topical corticosteroid treatment in EoE patients restored filaggrin expression, while reducing IL-20 subfamily cytokines. Abolishment of IL-20 subfamily signalling in Il20R2-/- animals attenuated experimental EoE in an OVA-induced mouse model. In the esophageal keratinocyte cell line, KYSE-180, we identified IL-20 subfamily-induced STAT3 and MAPK (ERK1/2) pathway activation. However, Stat3fl/flKrt5cre mice with an epithelium specific deletion of Stat3 developed exacerbated experimental EoE with a pronounced decrease of Flg2. In line, combined stimulation of patient-derived esophageal organoids with IL-20 subfamily cytokines and pharmacological inhibition of STAT3 resulted in aggravated decrease of FLG and FLG2. In addition, pharmacological STAT3 inhibition resulted in reduced transepithelial electrical resistance (TEER) and increased macromolecular flux in patient-derived air liquid interface (ALI) cultures. Whereas, inhibition of the MAPK (ERK1/2) pathway hampered IL-20 subfamily induced TEER reduction and paracellular flux increment. Finally, MAPK (ERK1/2) inhibitor treatment reduced infiltrating CD45+ immune cells in the esophagus and alleviated experimental EoE in mice. Conclusion We discovered a novel regulatory function of the IL-20 subfamily for epithelial barrier integrity. Aberrant IL-20 subfamily signaling disturbs the epithelial barrier function, while abrogation of IL-20 subfamily and ERK1/2 signaling restores epithelial integrity and attenuates experimental EoE. Therefore, we propose that targeting the IL-20 subfamily pathway could present a novel therapeutic strategy for EoE treatment.
Project description:Eosinophils are major effector cells in type 2 inflammatory responses and become activated in response to IL-4 and IL-33, yet the molecular mechanism remains unclear. We examined the direct effect of these cytokines on eosinophils and demonstrated that murine eosinophils respond to IL-4 and IL-33 by phosphorylation of STAT-6 and NFkB, respectively. RNA sequencing analysis of murine eosinophils indicated that IL-33 regulates 519 genes, whereas IL-4 regulates only 28 genes, including 19 IL-33-regulated genes. Interestingly, IL-33 induced eosinophil activation via two distinct mechanisms, IL-4 independent and IL-4 secretion/auto-stimulation dependent. Anti-IL-4 or anti-IL-4Ra antibody-treated eosinophils, as well as Il4- or Stat6-deficient eosinophils, had attenuated protein secretion of a subset of IL-33-induced genes, including Retnla and Ccl17. However, the induction of most IL-33-regulated transcripts (e.g. Il6 and Il13) was IL-4 independent and blocked by NFkB inhibition. Indeed, IL-33 induced the rapid release of pre-formed IL-4 protein from eosinophils by an NFkB-dependent mechanism. Thus, we have identified a novel activation pathway in murine eosinophils that is induced by IL-33 and differentially dependent upon IL-4. These data suggest that IL-4 plays a critical role in auto-amplification of IL-33-induced eosinophil activation and could be a potential target for therapeutic approaches in IL-33-related eosinophil-associated diseases. Low density bone marrow derived murine eosinophils were generated in culture over the period of 14 days. Eosinophils were activated by either IL-33 or IL-4 at 10 ng/ml for 1hr and 4hr. RNA was collected and subjected to next generation sequencing.
Project description:Eosinophils are elusive cells involved in allergic inflammation. Herein, we profiled 586 human eosinophils from the circulation and an allergic inflammatory site, the esophagus, of patients with eosinophilic esophagitis by Seq-Well–based single-cell RNA sequencing. The esophageal eosinophils were composed of a population of activated eosinophils (enriched in 659 genes compared with peripheral blood-associated eosinophils) and a small population of eosinophils resembling peripheral blood eosinophils (enriched in 62 genes compared with esophageal eosinophils). Esophageal eosinophils expressed genes involved in sensing and responding to diverse stimuli, most notably interferon-Ɣ(IFN-Ɣ), interleukin 10 (IL-10), histamine and leukotrienes, and succinate metabolite signaling. Esophageal eosinophils were most distinguished from other esophageal populations by gene expression of the receptors CCR3, HRH4, SUCNR1, and VSTM1; transcription factors CEBPE, OLIG1, and OLIG2; protease PRSS33; and hallmark eosinophil gene CLC. A web of bidirectional eosinophil interactions with other myeloid cells, T cells, fibroblasts, and the epithelium and vasculature was derived. Comparing esophageal eosinophils and mast cells revealed that esophageal eosinophils expressed genes involved in DAP12 interactions, IgG receptor-triggered events, immunoregulation, and IL-10 signaling, whereas esophageal mast cells expressed genes involved in arachidonic acid metabolism and response to unfolded proteins. These findings indicate that esophageal eosinophils exist as two populations, a minority population resembling blood eosinophils and the other population characterized by high de novo transcription of diverse sensing receptors and inflammatory mediators readying them to intersect with diverse cell types.
Project description:Patients with Eosinophilic esophagitis (EoE) require long-lasting resolution of inflammation to prevent fibrostenosis and dysphagia. However, the dissociation between symptoms and histologic improvement suggests persistent molecular drivers despite remission. We aimed to characterize persisting molecular alterations in pediatric patients with EoE using tissue proteomics. Esophageal tissue biopsies (n=151) and clinical data were collected prospectively from pediatric patients with EoE (N=34), gastroesophageal reflux disease (GERD; N=10; inflammatory controls) or functional disorders (FD; N=20; non-inflammatory controls). Biospies (n=131) acquired from the diagnostic endoscopy and up to 7 follow-ups were considered for proteome analysis in patients with EoE, while for GERD and FD only biopsies from initial diagnosis were included. Histologically active EoE (15 eosinophils per high power field (hpf)) was diagnosed in 79 biopsies and 52 samples derived from patients with EoE in remission (15 eosinophils per hpf). After microdissection of the epithelium proteins were extracted from the esophageal tissue followed by a liquid chromatography-tandem mass spectrometry. Proteomic analysis identified 3,704 different proteins in total across all samples.
Project description:Eosinophils are major effector cells in type 2 inflammatory responses and become activated in response to IL-4 and IL-33, yet the molecular mechanism remains unclear. We examined the direct effect of these cytokines on eosinophils and demonstrated that murine eosinophils respond to IL-4 and IL-33 by phosphorylation of STAT-6 and NFkB, respectively. RNA sequencing analysis of murine eosinophils indicated that IL-33 regulates 519 genes, whereas IL-4 regulates only 28 genes, including 19 IL-33-regulated genes. Interestingly, IL-33 induced eosinophil activation via two distinct mechanisms, IL-4 independent and IL-4 secretion/auto-stimulation dependent. Anti-IL-4 or anti-IL-4Ra antibody-treated eosinophils, as well as Il4- or Stat6-deficient eosinophils, had attenuated protein secretion of a subset of IL-33-induced genes, including Retnla and Ccl17. However, the induction of most IL-33-regulated transcripts (e.g. Il6 and Il13) was IL-4 independent and blocked by NFkB inhibition. Indeed, IL-33 induced the rapid release of pre-formed IL-4 protein from eosinophils by an NFkB-dependent mechanism. Thus, we have identified a novel activation pathway in murine eosinophils that is induced by IL-33 and differentially dependent upon IL-4. These data suggest that IL-4 plays a critical role in auto-amplification of IL-33-induced eosinophil activation and could be a potential target for therapeutic approaches in IL-33-related eosinophil-associated diseases.
Project description:Despite the well-recognized role of IL-13–induced transcriptional responses in allergic inflammation, the epigenetic mechanisms driven by IL-13 have not been well defined. We interrogated the transcriptional and epigenetic signatures of IL-13-induced epithelial responses focusing on the chromatin activation marks H3K4me3, H3K9Ac, and H3K27Ac. ChIP-sequencing analysis revealed that IL-13–inducible genes were epigenetically poised for induction and continued to accumulate epigenetic changes in response to IL-13. By intersecting the transcriptome and the epigenome of the IL-13 response, we identified neurotrophic tyrosine kinase receptor 1 (NTRK1) as a major target of IL-13 in epithelial cells. Using eosinophilic esophagitis as a model system for human allergic inflammation, we found that NTRK1 was dramatically induced in inflamed esophageal biopsies, and downstream mediators of NTRK1 signaling were elevated in diseased tissue. The NTRK1 ligand nerve growth factor (NGF) was constitutively expressed in control and disease states, indicating that induction of the receptor by IL-13 limited pathway activation. In epithelial cells, NGF and IL-13 synergistically induced transcription and secretion of the key eosinophil chemoattractant CCL26 (eotaxin-3). In summary, we demonstrate that IL-13–mediated allergic responses are epigenetically driven and identify NTRK1 as a novel epigenetic and transcriptional target of IL-13 that uniquely contributes to allergic inflammation. Human esophageal epithelial cell line TE-7 was stimulated with IL-13 at 100 ng/ml for 2 hr, 6 hr and 24 hr and subjected to RNA-sequencing. In parallel, TE-7 cells were induced with IL-13 for 6 hr and subjected to ChIP-sequencing analysis for H3K4me3, H3K9Ac and H3K27Ac activating chromatin marks.