Moss Alan C, Anton Pauline, Savidge Tor, Newman Paul, Cheifetz Adam S, Gay Jerome, Paraschos Sophia, Winter Michael Weinstein, Moyer Mary P, Karalis Katia, Kokkotou Efi, Pothoulakis Charalabos
Gastrointestinal Neuropeptide Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Gut. 2007 Sep;56(9):1210-7. doi: 10.1136/gut.2006.110668. Epub 2007 Apr 5.
BACKGROUND/AIMS: Urocortin II (UcnII) is a neuropeptide that binds with high affinity to the corticotropin-releasing hormone receptor 2 (CRHR2) in peripheral tissues. UcnII is synthesised in the intestine, but its role in human intestinal inflammation is largely unknown.
Responses of human colonic epithelial cells expressing CRHR2 to stimulation by UcnII were measured using ELISA, western blot analysis, real-time reverse transcription-PCR (RT-PCR) and interleukin (IL)8 promoter activity. Expression levels of CRHR2 and UcnII in human colitis were determined by immunofluorescence and real-time RT-PCR in mucosal biopsies from patients with Crohn's and ulcerative colitis, and in human intestinal xenografts after exposure to Clostridium difficile toxin A.
It is reported here that expression of CRHR2 mRNA and protein in human colonic epithelial cells (HT-29) are increased by exposure to C difficile toxin A or tumour necrosis factor (TNF)alpha. Stimulation of non-transformed NCM460 colonocytes overexpressing CRHR2alpha receptor with UcnII resulted in a time- and concentration-dependent increase in IL8 production. UcnII stimulation also led to activation of nuclear factor-kappaB (NF-kappaB) and mitogen-acivated protein (MAP) kinase in these cells, as evidenced by degradation of IkappaBalpha and phosphorylation of the p65 subunit of NF-kappaB and extracellularly regulated kinase (ERK) 1/2. Furthermore, expression of UcnII and CRHR2 mRNA was increased in mucosal samples of patients with inflammatory bowel disease, and after exposure of human intestinal xenografts to C difficile toxin A.
These results suggest that UcnII has pro-inflammatory effects in human intestinal cells via the CRHR2alpha receptor and may play an important role in the pathophysiology of colitis in humans.
背景/目的：尿皮质素II（UcnII）是一种神经肽，在外周组织中与促肾上腺皮质激素释放激素受体2（CRHR2）具有高亲和力结合。UcnII在肠道中合成，但其在人类肠道炎症中的作用尚不清楚。
使用酶联免疫吸附测定（ELISA）、蛋白质免疫印迹分析、实时逆转录聚合酶链反应（RT-PCR）和白细胞介素（IL）-8启动子活性，测定表达CRHR2的人结肠上皮细胞对UcnII刺激的反应。通过免疫荧光和实时RT-PCR，在克罗恩病和溃疡性结肠炎患者的黏膜活检组织以及暴露于艰难梭菌毒素A后的人肠道异种移植组织中，测定CRHR2和UcnII的表达水平。
本文报道，暴露于艰难梭菌毒素A或肿瘤坏死因子（TNF）α后，人结肠上皮细胞（HT-29）中CRHR2 mRNA和蛋白质的表达增加。用UcnII刺激过表达CRHR2α受体的未转化NCM460结肠细胞，导致IL-8产生呈时间和浓度依赖性增加。UcnII刺激还导致这些细胞中的核因子-κB（NF-κB）和丝裂原活化蛋白（MAP）激酶活化，这可通过IκBα降解以及NF-κB的p65亚基和细胞外调节激酶（ERK）1/2的磷酸化得到证实。此外，炎症性肠病患者的黏膜样本以及人肠道异种移植组织暴露于艰难梭菌毒素A后，UcnII和CRHR2 mRNA的表达增加。
这些结果表明，UcnII通过CRHR2α受体在人肠道细胞中具有促炎作用，可能在人类结肠炎的病理生理学中起重要作用。
