Brief Article
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World J Gastroenterol. Mar 7, 2013; 19(9): 1416-1423
Published online Mar 7, 2013. doi: 10.3748/wjg.v19.i9.1416
Corticotropin-releasing factor receptor subtype 2 in human colonic mucosa: Down-regulation in ulcerative colitis
Ekaterini Chatzaki, Peter A Anton, Mulugeta Million, Maria Lambropoulou, Theodoros Constantinidis, George Kolios, Yvette Taché, Dimitri E Grigoriadis
Ekaterini Chatzaki, Dimitri E Grigoriadis, Neurocrine Biosciences Inc., San Diego, CA 92121, United States
Ekaterini Chatzaki, George Kolios, Laboratory of Pharmacology, Faculty of Medicine, Democritus University of Thrace, 68100 Alexandroupolis, Greece
Peter A Anton, Center for HIV Prevention Research, Division of Digestive Diseases, University of California at Los Angeles, and VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States
Peter A Anton, Mulugeta Million, Yvette Taché, Digestive Diseases Research Center and Center for Neurobiology of Stress, Division of Digestive Diseases, University of California at Los Angeles, and VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073, United States
Maria Lambropoulou, Laboratory of Histology-Embryology, Faculty of Medicine, Democritus University of Thrace, 68100 Alexandroupolis, Greece
Theodoros Constantinidis, Laboratory of Hygiene and Environmental Protection, Faculty of Medicine, Democritus University of Thrace, 68100 Alexandroupolis, Greece
Author contributions: Chatzaki E, Taché Y and Grigoriadis DE designed the research; Chatzaki E, Million M and Lambropoulou M performed the research; Anton PA contributed new reagents/analytic tools/tissues; Constantinidis T and Kolios G analyzed the data; Chatzaki E and Taché Y wrote the paper.
Supported by The National Institute of Diabetes and Digestive and Kidney Diseases R01 grant DK-57238; Center Grant DK-41301 (Clinical core); Veteran Administration Research Career Scientist Award (YT); and NIH DK-78676 (MM)
Correspondence to: Ekaterini Chatzaki, PhD, Associate Professor, Laboratory of Pharmacology, Faculty of Medicine, Democritus University of Thrace, Dragana, 68100 Alexandroupolis, Greece. achatzak@med.duth.gr
Telephone: +30-255-1030533 Fax: +30-255-1030533
Received: August 31, 2012
Revised: December 11, 2012
Accepted: December 20, 2012
Published online: March 7, 2013
Processing time: 192 Days and 21 Hours
Abstract

AIM: To assess corticotropin-releasing factor receptor 2 (CRF2) expression in the colon of healthy subjects and patients with ulcerative colitis (UC).

METHODS: We examined CRF2 gene and protein expression in the distal/sigmoid colonic mucosal biopsies from healthy subjects and patients with UC (active or disease in remission), human immunodeficiency virus (HIV) and functional bowel disease (FBD) by reverse transcription-polymerase chain reaction and immunofluorescence.

RESULTS: Gene expression of CRF2 was demonstrated in the normal human colonic biopsies, but not in the human colorectal adenocarcinoma cell line Caco2. Receptor protein localization showed immunoreactive CRF2 receptors in the lamina propria and in the epithelial cells of the distal/sigmoid biopsy samples. Interestingly, CRF2 immunoreactivity was no longer observed in epithelial cells of patients with mild-moderately active UC and disease in remission, while receptor protein expression did not change in the lamina propria. No differences in CRF2 expression profile were observed in distal/sigmoid intestinal biopsies from HIV infection and FBD patients, showing no signs of inflammation.

CONCLUSION: The down-regulation of the CRF2 receptor in the distal/sigmoid biopsies of UC patients is indicative of change in CRF2 signalling associated with the process of inflammation.

Keywords: Colonic mucosa, Corticotropin-releasing factor, Corticotropin-releasing factor receptor, Human immunodeficiency virus, Ulcerative colitis, Urocortin