ORCID Profile
0000-0003-3827-8473
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Publisher: Oxford University Press (OUP)
Date: 09-05-2019
DOI: 10.1093/IBD/IZZ070
Abstract: Intestinal fibrosis is a common and serious complication of Crohn’s disease characterized by the accumulation of fibroblasts, deposition of extracellular matrix, and formation of scar tissue. Although many factors including cytokines and proteases contribute to the development of intestinal fibrosis, the initiating mechanisms and the complex interplay between these factors remain unclear. Chronic infection of mice with Salmonella enterica serovar Typhimurium was used to induce intestinal fibrosis. A murine protease-specific CLIP-CHIP microarray analysis was employed to assess regulation of proteases and protease inhibitors. To confirm up- or downregulation during fibrosis, we performed quantitative real-time polymerase chain reaction (PCR) and immunohistochemical stainings in mouse tissue and tissue from patients with inflammatory bowel disease. In vitro infections were used to demonstrate a direct effect of bacterial infection in the regulation of proteases. Mice develop severe and persistent intestinal fibrosis upon chronic infection with Salmonella enterica serovar Typhimurium, mimicking the pathology of human disease. Microarray analyses revealed 56 up- and 40 downregulated proteases and protease inhibitors in fibrotic cecal tissue. Various matrix metalloproteases, serine proteases, cysteine proteases, and protease inhibitors were regulated in the fibrotic tissue, 22 of which were confirmed by quantitative real-time PCR. Proteases demonstrated site-specific staining patterns in intestinal fibrotic tissue from mice and in tissue from human inflammatory bowel disease patients. Finally, we show in vitro that Salmonella infection directly induces protease expression in macrophages and epithelial cells but not in fibroblasts. In summary, we show that chronic Salmonella infection regulates proteases and protease inhibitors during tissue fibrosis in vivo and in vitro, and therefore this model is well suited to investigating the role of proteases in intestinal fibrosis.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2020
DOI: 10.1002/HEP.31140
Abstract: T cells from patients with primary sclerosing cholangitis (PSC) show a prominent interleukin (IL)‐17 response upon stimulation with bacteria or fungi, yet the reasons for this dominant T‐helper 17 (Th17) response in PSC are not clear. Here, we analyzed the potential role of monocytes in microbial recognition and in skewing the T‐cell response toward Th17. Monocytes and T cells from blood and livers of PSC patients and controls were analyzed ex vivo and in vitro using transwell experiments with cholangiocytes. Cytokine production was measured using flow cytometry, enzyme‐linked immunosorbent assay, RNA in situ hybridization, and quantitative real‐time PCR. Genetic polymorphisms were obtained from ImmunoChip analysis. Following e x vivo stimulation with phorbol myristate acetate/ionomycin, PSC patients showed significantly increased numbers of IL‐17A–producing peripheral blood CD4 + T cells compared to PBC patients and healthy controls, indicating increased Th17 differentiation in vivo . Upon stimulation with microbes, monocytes from PSC patients produced significantly more IL‐1β and IL‐6, cytokines known to drive Th17 cell differentiation. Moreover, microbe‐activated monocytes induced the secretion of Th17 and monocyte‐recruiting chemokines chemokine (C‐C motif) ligand (CCL)‐20 and CCL‐2 in human primary cholangiocytes. In livers of patients with PSC cirrhosis, CD14 hi CD16 int and CD14 lo CD16 hi monocytes/macrophages were increased compared to alcoholic cirrhosis, and monocytes were found to be located around bile ducts. PSC patients show increased Th17 differentiation already in vivo . Microbe‐stimulated monocytes drive Th17 differentiation in vitro and induce cholangiocytes to produce chemokines mediating recruitment of Th17 cells and more monocytes into portal tracts. Taken together, these results point to a pathogenic role of monocytes in patients with PSC.
No related grants have been discovered for Stephanie Stein.