title: Corticotropin-Releasing Hormone Receptor 2 Signaling Promotes Mucosal Repair Responses after Colitis.
abstract: The corticotropin-releasing hormone family mediates functional responses in many organs, including the intestine. Activation of corticotropin-releasing hormone receptor 2 (CRHR2) in the colonic mucosa promotes inflammation during acute colitis but inhibits inflammation during chronic colitis. We hypothesized that specific modulation of CRHR2 signaling in the colonic mucosa can promote restoration of the epithelium through stimulation of cell proliferative, migratory, and wound healing responses. Mucosal repair was assessed after dextran sodium sulfate (DSS)-induced colitis in mice receiving intracolonic injections of a CRHR2 antagonist or vehicle and in Crhr2(-/-) mice. Histologic damage, cytokine expression, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, and Ki-67 immunoreactivity were evaluated. Cell viability, proliferation, and migration were compared between parental and CRHR2-overexpressing colonic epithelial cells. Protein lysates were processed for phosphoprotein assays and a wound healing assay performed in vitro. Administration of a CRHR2 antagonist after DSS-induced colitis increased disease activity, delayed healing, and decreased epithelial cell proliferation in vivo. Colons from these mice also showed increased apoptosis and proinflammatory cytokine expression. Compared with controls, Crhr2(-/-) mice showed increased mortality in the DSS healing protocol. CRHR2-overexpressing cells had increased proliferation and migration compared with parental cells. Wound healing and signal transducer and activator of transcription 3 activity were elevated in CRHR2-overexpressing cells after urocortin 2 and IL-6 treatment, suggesting advanced healing progression. Our results suggest that selective CRHR2 activation may provide a targeted approach to enhance mucosal repair pathways after colitis.
authors.affiliation: Center for Inflammatory Bowel Diseases, Division of Digestive Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Hoffman
authors.affiliation: Center for Inflammatory Bowel Diseases, Division of Digestive Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
authors.forename: Stavroula
authors.initials: S
authors.lastname: Baritaki
authors.affiliation: Center for Inflammatory Bowel Diseases, Division of Digestive Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Ruiz
authors.affiliation: Center for Inflammatory Bowel Diseases, Division of Digestive Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
authors.forename: Aristea
authors.initials: A
authors.lastname: Sideri
authors.affiliation: Center for Inflammatory Bowel Diseases, Division of Digestive Diseases, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California. Electronic address: cpothoulakis@mednet.ucla.edu.
authors.forename: Charalabos
authors.initials: C
authors.lastname: Pothoulakis
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D003092:Colitis / Q000378:metabolism* / Q000473:pathology*; D004195:Disease Models, Animal; D055785:Gene Knockdown Techniques; D006801:Humans; D007118:Immunoassay; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018345:Mice, Knockout; D060888:Real-Time Polymerase Chain Reaction; D018019:Receptors, Corticotropin-Releasing Hormone / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction; D014945:Wound Healing / Q000502:physiology
chemical_list: C101531:CRF receptor type 2; D018019:Receptors, Corticotropin-Releasing Hormone