Somatostatin regulates NHE8 protein expression via the ERK1/2 MAPK pathway in DSS-induced colitis mice.
Previous studies reported that administration of somatostatin (SST) to human patients mitigated their diarrheal symptoms. Octreotide (an analog of SST) treatment in animals resulted in upregulation of sodium/hydrogen exchanger 8 (NHE8). NHE8 is important for water/sodium absorption in the intestine, and loss of NHE8 function results in mucosal injury. Thus we hypothesized that NHE8 expression is inhibited during colitis and that SST treatment during pathological conditions can restore NHE8 expression. Our data showed for the first time that NHE8 is expressed in the human colonic tissue and that NHE8 expression is decreased in ulcerative colitis (UC) patients. We also found that octreotide could stimulate colonic NHE8 expression in colitic mice. Furthermore, the somatostatin receptor 2 (SSTR2) agonist seglitide and the somatostatin receptor 5 (SSTR5) agonist L-817,818 could restore NHE8 expression via its role in suppressing ERK1/2 phosphorylation. Our study uncovered a novel mechanism of SST stimulation of NHE8 expression in colitis.
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Xiao
X
Li
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Lin
L
Cai
Department of Pediatrics, The University of Arizona, Tucson, Arizona.
Hua
H
Xu
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Chong
C
Geng
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Jing
J
Lu
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Liping
L
Tao
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and.
Dan
D
Sun
Department of Pediatrics, The University of Arizona, Tucson, Arizona.
Fayez K
FK
Ghishan
Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, China; and wangch@scu.edu.cn.
Chunhui
C
Wang
D000328:Adult; D000818:Animals; D018938:Caco-2 Cells; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D005260:Female; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008875:Middle Aged; D015282:Octreotide / Q000494:pharmacology; D017481:Receptors, Somatostatin / Q000378:metabolism; D012007:Rectum / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology*
D005765:Gastrointestinal Agents; D017481:Receptors, Somatostatin; C471945:Slc9a8 protein, mouse; D017923:Sodium-Hydrogen Exchangers; D013004:Somatostatin; D015282:Octreotide
NHE8; SSTR2; SSTR5; inflammatory bowel disease; somatostatin
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