Huatuo Zhu1, Shujun Huang1, Min Yue1, Wenguo Chen1, Chao Lu1, Xinhe Lou1, Chunxiao Li1, Guodong Shan1, Hongtan Chen1, Xiaowei Xu1, Guoqiang Xu2, Lihua Chen3. 1. Department of Gastroenterology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qingchun Road, Hangzhou, 310003, People's Republic of China. 2. Department of Gastroenterology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qingchun Road, Hangzhou, 310003, People's Republic of China. xgqcht@163.com. 3. Department of Gastroenterology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79 Qingchun Road, Hangzhou, 310003, People's Republic of China. 21218027@zju.edu.cn.
Abstract
BACKGROUND: Ulcerative colitis (UC) is an idiopathic colonic mucosal disease, and its pathogenesis has not been fully understood. Up-frameshift protein 1 (UPF1) is a potential molecule for UC predicted by a computational approach. AIM: The present study aimed to validate the underlying mechanism of UPF1 in UC. METHODS: UPF1 expression was detected by qRT-PCR, western blotting, and immunohistochemistry in dextran sulfate sodium-induced colitis in mice. To simulate the intestinal inflammation microenvironment, NCM460 human colonic epithelial cells were exposed to a mixture of inflammatory mediators. The potential mechanism involving TNFR1-NF-κB/MAPKs pathway activation was addressed by western blotting, reporter gene assays, and siRNA (siUPF1) or UPF1-expressing plasmid pENTER-transfected cells. RESULTS: UPF1 was downregulated in colonic epithelial cells of colitic mice, and in vitro, contrary to the mRNA levels of the associated cytokines enhanced in the UPF1 dysregulation group within stimulatory factors, most relevant cytokines were significantly decreased in UPF1 overexpression group. Mechanistically, the increased expression of tumor necrosis factor receptor 1 (TNFR1) was found in NCM460 cells pre-treated with siUPF1, with the activation of IKK/NF-κB and MAPKs pathways, including JNK/AP-1 and P38, but not the ERK1/2 pathway. Moreover, the repression of TNFR1 required the interaction of UPF1 with the promoter. CONCLUSION: UPF1, which negatively regulated the transcription of TNFR1, is a novel factor regulating intestinal inflammation. The downregulation of UPF1 activated the TNFR1-dependent NF-κB/MAPKs pathway, and promoting inflammatory responses in colon might act as a causal role in UC.
BACKGROUND:Ulcerative colitis (UC) is an idiopathic colonic mucosal disease, and its pathogenesis has not been fully understood. Up-frameshift protein 1 (UPF1) is a potential molecule for UC predicted by a computational approach. AIM: The present study aimed to validate the underlying mechanism of UPF1 in UC. METHODS:UPF1 expression was detected by qRT-PCR, western blotting, and immunohistochemistry in dextran sulfate sodium-induced colitis in mice. To simulate the intestinal inflammation microenvironment, NCM460 human colonic epithelial cells were exposed to a mixture of inflammatory mediators. The potential mechanism involving TNFR1-NF-κB/MAPKs pathway activation was addressed by western blotting, reporter gene assays, and siRNA (siUPF1) or UPF1-expressing plasmid pENTER-transfected cells. RESULTS:UPF1 was downregulated in colonic epithelial cells of colitic mice, and in vitro, contrary to the mRNA levels of the associated cytokines enhanced in the UPF1 dysregulation group within stimulatory factors, most relevant cytokines were significantly decreased in UPF1 overexpression group. Mechanistically, the increased expression of tumor necrosis factor receptor 1 (TNFR1) was found in NCM460 cells pre-treated with siUPF1, with the activation of IKK/NF-κB and MAPKs pathways, including JNK/AP-1 and P38, but not the ERK1/2 pathway. Moreover, the repression of TNFR1 required the interaction of UPF1 with the promoter. CONCLUSION:UPF1, which negatively regulated the transcription of TNFR1, is a novel factor regulating intestinal inflammation. The downregulation of UPF1 activated the TNFR1-dependent NF-κB/MAPKs pathway, and promoting inflammatory responses in colon might act as a causal role in UC.
Authors: Arianna Nenci; Christoph Becker; Andy Wullaert; Ralph Gareus; Geert van Loo; Silvio Danese; Marion Huth; Alexei Nikolaev; Clemens Neufert; Blair Madison; Deborah Gumucio; Markus F Neurath; Manolis Pasparakis Journal: Nature Date: 2007-03-14 Impact factor: 49.962