Urocortin II mediates pro-inflammatory effects in human colonocytes via corticotropin-releasing hormone receptor 2alpha.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Moss
Alan C
AC
Gastrointestinal Neuropeptide Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Anton
Pauline
P
Savidge
Tor
T
Newman
Paul
P
Cheifetz
Adam S
AS
Gay
Jerome
J
Paraschos
Sophia
S
Winter
Michael Weinstein
MW
Moyer
Mary P
MP
Karalis
Katia
K
Kokkotou
Efi
E
Pothoulakis
Charalabos
C
D000818:Animals; D001427:Bacterial Toxins / Q000276:immunology; D002460:Cell Line; D003092:Colitis / Q000276:immunology; D003093:Colitis, Ulcerative / Q000276:immunology; D003106:Colon / Q000166:cytology / Q000276:immunology*; D003346:Corticotropin-Releasing Hormone / Q000276:immunology*; D003424:Crohn Disease / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology; D004847:Epithelial Cells / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology; D007422:Intestines / Q000637:transplantation; D051379:Mice; D016513:Mice, SCID; D020928:Mitogen-Activated Protein Kinases / Q000276:immunology; D016328:NF-kappa B / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D018019:Receptors, Corticotropin-Releasing Hormone / Q000276:immunology*; D014183:Transplantation, Heterologous; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D054832:Urocortins
D001427:Bacterial Toxins; C101531:CRF receptor type 2; D004768:Enterotoxins; D016209:Interleukin-8; D016328:NF-kappa B; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; D014409:Tumor Necrosis Factor-alpha; C426705:UCN2 protein, human; D054832:Urocortins; C041348:tcdA protein, Clostridium difficile; C518358:urocortin 2, mouse; D003346:Corticotropin-Releasing Hormone; D020928:Mitogen-Activated Protein Kinases