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:The microenvironment of injured mucosa has important effects on intestinal stem cell self-renewal and reconstruction of epithelial barrier function in inflammatory bowel disease (IBD). However, the precise status of the interactions between intestinal epithelial cell (IEC) injury, particularly intestinal crypt absence, and microenvironment in IBD is not completely understood. We identified miR-494-3p as important for protection of colonic stemness in intestinal inflammation colonic organoid culture. A novel cytokine-cytokine receptor, EDA-A2/EDA2R, could suppress colonic stemness and epithelial repair during IBD. During intestinal inflammation, high level of LP macrophage-derived EDA-A2 inhibited the nuclear β-catenin/c-Myc axis and organoid growth by targeting EDA2R in colonic crypt stem cells. We further demonstrated that the pro-inflammatory cytokines IL-1β and IL-6 are capable of stimulating macrophages to release EDA-A2 during colitis. Secondly, we identified the cross-talk among IECs, colonic crypts, and lamina propria (LP) macrophages in miR-494-3p-mediated colitis. Furthermore, our study showed that miR-494-3p deficiency in IECs promoted LP macrophage recruitment and M1 activation in DSS-induced colitis mice. In addition, we identified miR-494-3p as critical to dampening IEC injury; specifically, miR-494-3p inhibited inflammation-induced IKKβ/NF-κB activation by targeting the IKKβ 3’UTR in IECs. As such, administration of adequate amounts of a miR-494-3p agomire attenuate colitis in vivo. Consistent with this inference, we showed that miR-494-3p levels were decreased in colonic crypts and serum in colitis mice, and loss of miR-494 potentiated the severity of colonic colitis. Our clinical data on the interactions between miR-494-3p levels in serum exosomes & colonic tissues and associated outcomes support the clinical relevance of miR-494-3p in IBD. The miR-494-3p agomir system, which we designed permits local delivery in vivo in this study, significantly ameliorated the severity of colonic colitis. Our findings no only uncover a miR-494-3p-mediated cross-talk mechanism by which inflamed colonic LP macrophages integrate signals from IECs to regulate colonic stemness and colonic epithelial repair/homeostasis. The miR-494-3p agomir may serve as a potential therapeutic approach in IBD.

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Analysis of HOIL1-dependent gene expression in the murine small intestine

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