Background: Fistulas represent a frequent and severe complication in patients with Crohn disease (CD). Tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta, and interleukin (IL)... Show moreBackground: Fistulas represent a frequent and severe complication in patients with Crohn disease (CD). Tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta, and interleukin (IL)-13 are known to trigger epithelial-mesenchymal transition (EMT), promoting fistula formation. Here, we investigated the role of T-lymphocytes (T cells) in fistula pathogenesis.Methods: CD3(+)CD8(-), CD3(+)CD8(+), or CD45(+)CD3(-) cells from healthy volunteers, patients with CD, and patients with CD with perianal fistula were co-cultured with HT-29 cells. The EMT, cytokine production, and mRNA expression were analyzed. Perianal CD fistula specimens were immunohistochemically stained for cytokines and their receptors. The effect of cytokines on EMT induction was investigated using an EMT spheroid model.Results: Patients with CD with fistula revealed more CD3(+)CD8(-) and less CD3(+)CD8(+) T cells in blood than healthy control patients and patients with CD without fistula. In perianal fistula specimens, CD4(+) cells-and to a lesser extent CD8(+) cells-were highly present around fistula tracts. When co-cultured with HT-29 cells, both cell subsets promoted EMT-related gene expression and TNF-alpha production in a time-dependent manner. The CD3(+)CD8(-) T cells from patients with CD with fistula also produced higher amounts of IL-13 than cells from healthy control patients or patients with CD without a fistula. We found that IL-22 and IL-22R(alpha 1) were highly expressed in perianal CD fistula specimens and that IL-22 cotreatment potentiated TNF-alpha-induced EMT in HT-29 spheroids.Conclusions: Our data indicate that both CD3(+)CD8(-) and CD3(+)CD8(+) T cells play an important role in the pathogenesis of perianal CD fistulas by the secretion of TNF-alpha. Our data support clinical evidence indicating that anti-TNF-alpha therapy is effective in fistula treatment and identify IL-13 and IL-22 as possible novel therapeutic targets for fistula therapy. Show less
Background Fistulas represent a frequent and severe complication in patients with Crohn disease (CD). Tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta, and interleukin (IL)... Show moreBackground Fistulas represent a frequent and severe complication in patients with Crohn disease (CD). Tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta, and interleukin (IL)-13 are known to trigger epithelial-mesenchymal transition (EMT), promoting fistula formation. Here, we investigated the role of T-lymphocytes (T cells) in fistula pathogenesis. Methods CD3(+)CD8(-), CD3(+)CD8(+), or CD45(+)CD3(-) cells from healthy volunteers, patients with CD, and patients with CD with perianal fistula were co-cultured with HT-29 cells. The EMT, cytokine production, and mRNA expression were analyzed. Perianal CD fistula specimens were immunohistochemically stained for cytokines and their receptors. The effect of cytokines on EMT induction was investigated using an EMT spheroid model. Results Patients with CD with fistula revealed more CD3(+)CD8(-) and less CD3(+)CD8(+) T cells in blood than healthy control patients and patients with CD without fistula. In perianal fistula specimens, CD4(+) cells-and to a lesser extent CD8(+) cells-were highly present around fistula tracts. When co-cultured with HT-29 cells, both cell subsets promoted EMT-related gene expression and TNF-alpha production in a time-dependent manner. The CD3(+)CD8(-) T cells from patients with CD with fistula also produced higher amounts of IL-13 than cells from healthy control patients or patients with CD without a fistula. We found that IL-22 and IL-22R(alpha 1) were highly expressed in perianal CD fistula specimens and that IL-22 cotreatment potentiated TNF-alpha-induced EMT in HT-29 spheroids. Conclusions Our data indicate that both CD3(+)CD8(-) and CD3(+)CD8(+) T cells play an important role in the pathogenesis of perianal CD fistulas by the secretion of TNF-alpha. Our data support clinical evidence indicating that anti-TNF-alpha therapy is effective in fistula treatment and identify IL-13 and IL-22 as possible novel therapeutic targets for fistula therapy. Show less
Pachera, E.; Assassi, S.; Salazar, G.A.; Stellato, M.; Renoux, F.; Wunderlin, A.; ... ; Distler, O. 2020
TGF-beta is a master regulator of fibrosis, driving the differentiation of fibroblasts into apoptosis-resistant myofibroblasts and sustaining the production of extracellular matrix (ECM) components... Show moreTGF-beta is a master regulator of fibrosis, driving the differentiation of fibroblasts into apoptosis-resistant myofibroblasts and sustaining the production of extracellular matrix (ECM) components. Here, we identified the nuclear long noncoding RNA (lncRNA) H19X as a master regulator of TGF-beta-driven tissue fibrosis. H19X was consistently upregulated in a wide variety of human fibrotic tissues and diseases and was strongly induced by TGF-beta, particularly in fibroblasts and fibroblast-related cells. Functional experiments following H19X silencing revealed that H19X was an obligatory factor for TGF-beta-induced ECM synthesis as well as differentiation and survival of ECM-producing myofibroblasts. We showed that H19X regulates DDIT4L gene expression, specifically interacting with a region upstream of the DDIT4L gene and changing the chromatin accessibility of a DDIT4L enhancer. These events resulted in transcriptional repression of DDIT4L and, in turn, in increased collagen expression and fibrosis. Our results shed light on key effectors of TGF-beta-induced ECM remodeling and fibrosis. Show less
Up till now, research on inflammatory bowel disease [IBD] has mainly been focused on the immune cells present in the gastrointestinal tract. However, recent insights indicate that stromal cells... Show moreUp till now, research on inflammatory bowel disease [IBD] has mainly been focused on the immune cells present in the gastrointestinal tract. However, recent insights indicate that stromal cells also play an important and significant role in IBD pathogenesis. Stromal cells in the intestines regulate both intestinal epithelial and immune cell homeostasis. Different subsets of stromal cells have been found to play a role in other inflammatory diseases [e.g. rheumatoid arthritis], and these various stromal subsets now appear to carry out also specific functions in the inflamed gut in IBD. Novel potential therapies for IBD utilize, as well as target, these pathogenic stromal cells. Injection of mesenchymal stromal cells [MSCs] into fistula tracts of Crohn's disease patients is already approved and used in clinical settings. In this review we discuss the current knowledge of the role of stromal cells in IBD pathogenesis. We further outline recent attempts to modify the stromal compartment in IBD with agents that target or replace the pathogenic stroma. Show less
