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3.
Article in English | WPRIM (Western Pacific) | ID: wpr-142453

ABSTRACT

Abnormal levels of microRNA (miR)-155, which regulate inflammation and immune responses, have been demonstrated in the colonic mucosa of patients with inflammatory bowel diseases (IBD), although its role in disease pathophysiology is unknown. We investigated the role of miR-155 in the acquisition and maintenance of an activated phenotype by intestinal myofibroblasts (IMF), a key cell population contributing to mucosal damage in IBD. IMF were isolated from colonic biopsies of healthy controls, ulcerative colitis (UC) and Crohn's disease (CD) patients. MiR-155 in IMF was quantified by quantitative reverse transcription-PCR in basal condition and following exposure to TNF-alpha, interleukin (IL)-1beta, lipopolysaccharide (LPS) or TGF-beta1. The effects of miR-155 mimic or inhibitor transfection on cytokine release and suppressor of cytokine signaling 1 (SOCS1) expression were assessed by enzyme-linked immunosorbent assay and western blot, respectively. Regulation of the target gene SOCS1 expression by miR-155 was assessed using luciferase reporter construct. We found that miR-155 was significantly upregulated in UC as compared with control- and CD-derived IMF. Moreover, TNF-alpha and LPS, but not TGF-beta1 and IL-1beta, significantly increased miR-155 expression in IMF. Ectopic expression of miR-155 in control IMF augmented cytokines release, whereas it downregulated SOCS1 expression. MiR-155 knockdown in UC-IMF reduced cytokine production and enhanced SOCS1 expression. Luciferase reporter assay demonstrated that miR-155 directly targets SOCS1. Moreover, silencing of SOCS1 in control IMF significantly increased IL-6 and IL-8 release. In all, our data suggest that inflammatory mediators induce miR-155 expression in IMF of patients with UC. By downregulating the expression of SOCS1, miR-155 wires IMF inflammatory phenotype.


Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Cells, Cultured , Colitis, Ulcerative/genetics , Cytokines/immunology , Gene Expression Regulation , Intestinal Mucosa/immunology , MicroRNAs/genetics , Myofibroblasts/immunology , Suppressor of Cytokine Signaling Proteins/genetics , Tumor Necrosis Factor-alpha/immunology , Up-Regulation
4.
Article in English | WPRIM (Western Pacific) | ID: wpr-142452

ABSTRACT

Abnormal levels of microRNA (miR)-155, which regulate inflammation and immune responses, have been demonstrated in the colonic mucosa of patients with inflammatory bowel diseases (IBD), although its role in disease pathophysiology is unknown. We investigated the role of miR-155 in the acquisition and maintenance of an activated phenotype by intestinal myofibroblasts (IMF), a key cell population contributing to mucosal damage in IBD. IMF were isolated from colonic biopsies of healthy controls, ulcerative colitis (UC) and Crohn's disease (CD) patients. MiR-155 in IMF was quantified by quantitative reverse transcription-PCR in basal condition and following exposure to TNF-alpha, interleukin (IL)-1beta, lipopolysaccharide (LPS) or TGF-beta1. The effects of miR-155 mimic or inhibitor transfection on cytokine release and suppressor of cytokine signaling 1 (SOCS1) expression were assessed by enzyme-linked immunosorbent assay and western blot, respectively. Regulation of the target gene SOCS1 expression by miR-155 was assessed using luciferase reporter construct. We found that miR-155 was significantly upregulated in UC as compared with control- and CD-derived IMF. Moreover, TNF-alpha and LPS, but not TGF-beta1 and IL-1beta, significantly increased miR-155 expression in IMF. Ectopic expression of miR-155 in control IMF augmented cytokines release, whereas it downregulated SOCS1 expression. MiR-155 knockdown in UC-IMF reduced cytokine production and enhanced SOCS1 expression. Luciferase reporter assay demonstrated that miR-155 directly targets SOCS1. Moreover, silencing of SOCS1 in control IMF significantly increased IL-6 and IL-8 release. In all, our data suggest that inflammatory mediators induce miR-155 expression in IMF of patients with UC. By downregulating the expression of SOCS1, miR-155 wires IMF inflammatory phenotype.


Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Cells, Cultured , Colitis, Ulcerative/genetics , Cytokines/immunology , Gene Expression Regulation , Intestinal Mucosa/immunology , MicroRNAs/genetics , Myofibroblasts/immunology , Suppressor of Cytokine Signaling Proteins/genetics , Tumor Necrosis Factor-alpha/immunology , Up-Regulation
5.
World J Gastroenterol ; 11(34): 5303-8, 2005 Sep 14.
Article in English | MEDLINE | ID: mdl-16149136

ABSTRACT

AIM: To focus on the role of CD40 and CD40L in their pathogenesis. METHODS: We analyzed by immunohistochemistry the CD40 and CD40L expression in the pouch mucosa of 28 patients who had undergone RPC for UC, in the terminal ileum of 6 patients with UC and 11 healthy subjects. We also examined by flow cytometry the expression of CD40 by B lymphocytes and monocytes in the peripheral blood of 20 pouch patients, 15 UC patients and 11 healthy controls. RESULTS: Ileal pouch mucosa leukocytes presented a significantly higher expression of CD40 and CD40L as compared to controls. This alteration correlated with pouchitis, but was also present in the healthy pouch and in the terminal ileum of UC patients. CD40 expression of peripheral B lymphocytes was significantly higher in patients with UC and pouch, respect to controls. Increased CD40 levels in blood B cells of pouch patients correlated with the presence of spondyloarthropathy, but not with pouchitis, or inflammatory indices. CONCLUSION: High CD40 expression in the ileal pouch mucosa could be implied in the pathogenesis of pouchitis following proctocolectomy for UC, whereas its increased levels on peripheral blood B lymphocytes are associated with the presence of extraintestinal manifestations.


Subject(s)
CD40 Antigens/metabolism , CD40 Ligand/metabolism , Colitis, Ulcerative/metabolism , Colitis, Ulcerative/surgery , Proctocolectomy, Restorative , Adult , Female , Humans , Immunohistochemistry , Male , Middle Aged , Postoperative Complications/metabolism , Pouchitis/metabolism
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