title: P2Y(2)  receptor expression is regulated by C/EBPβ during inflammation in intestinal epithelial cells.
abstract: Inflammatory bowel diseases are characterized by relapses and remission periods during which numerous factors, including stress factors and nucleotides, are mobilized to re-establish intestinal mucosal homeostasis. We have previously found that expression of the P2Y(2) nucleotide receptor is increased in colonic tissue isolated from inflammatory bowel disease patients as well as in a mouse model of colitis, and that P2Y(2) transcription is regulated in part by nuclear factor κB (NF-κB) p65. Transcription factor DNA-binding site analysis identified three potential CCAAT/enhancer-binding protein β (C/EBPβ) binding sites in the P2Y(2) proximal promoter. We then assessed the role of C/EBP transcription factors in the regulation of P2Y(2) in intestinal epithelial cells (IECs). We identified a region between -229 and -220 bp upstream of the transcription initiation site as a DNA-binding site for C/EBPβ, by electrophoretic mobility and supershift assays. Mutagenesis of this site decreased C/EBPβ-dependent P2Y(2) expression, as assessed by luciferase assays. In vivo, C/EBPβ as well as P2Y(2) expression was increased in colonic IECs isolated from mice with dextran sulfate sodium-induced acute colitis. In contrast, P2Y(2) expression was decreased in C/EBPβ-deficient mice treated with dextran sulfate sodium. Although C/EBPβ was sufficient to induce P2Y(2) transcription, the effect of C/EBPβ and NF-κB p65 on receptor transcription was synergistic. Chromatin immunoprecipitation assays revealed that both proteins simultaneously bind to the P2Y(2) promoter. Thus, we have identified C/EBPβ as a novel regulator of P2Y(2) expression.
authors: Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
authors: Emilie
authors: E
authors: Degagné
authors: Naomie
authors: N
authors: Turgeon
authors: Julie
authors: J
authors: Moore-Gagné
authors: Claude
authors: C
authors: Asselin
authors: Fernand-Pierre
authors: FP
authors: Gendron
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000502:physiology*; D018938:Caco-2 Cells; D003092:Colitis / Q000139:chemically induced; D016264:Dextran Sulfate; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000503:physiopathology*; D051379:Mice; D016328:NF-kappa B / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D051381:Rats; D058473:Receptors, Purinergic P2Y2 / Q000096:biosynthesis*
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D016328:NF-kappa B; D058473:Receptors, Purinergic P2Y2; D016264:Dextran Sulfate