title: Identification of a novel substance P (SP)-neurokinin-1 receptor (NK-1R) microRNA-221-5p inflammatory network in human colonic epithelial cells.
abstract: OBJECTIVE
  Substance P (SP), a neuropeptide member of the tachykinin family, plays a critical role in colitis. MicroRNAs (miRNAs) are small non-coding RNAs that negatively regulate gene expression. However, whether SP modulates expression of microRNAs in human colonic epithelial cells remains unknown.
  
  
  METHODS
  We performed microRNA profiling analysis of SP-stimulated human colonic epithelial NCM460 cells overexpressing neurokinin-1 receptor (NCM460-NK-1R). Targets of SP-regulated microRNAs were validated by real time polymerase chain reaction (RT-PCR). Functions of miRNAs were tested in NCM460-NK-1R cells and the TNBS and DSS models of colitis.
  
  
  RESULTS
  SP stimulated differential expression of 29 microRNAs, including miR-221-5p, the highest up regulated miR (by 12.6-fold) upon SP stimulation. Bioinformatic and luciferase reporter analyses identified interleukin 6 receptor (IL-6R) mRNA as a direct target of miR-221-5p in NCM460 cells. Accordingly, SP exposure of NCM460-NK-1R cells increased IL-6R mRNA expression, while overexpression of miR-221-5p reduced IL-6R expression. NF-κB and JNK inhibition decreased SP-induced miR-221-5p expression. MiR-221-5p expression was increased in both TNBS- and DSS-induced colitis and colonic biopsies from Ulcerative Colitis, but not Crohn's Disease subjects, compared to controls. In mice, intracolonic administration of a miR-221-5p chemical inhibitor, exacerbated TNBS-and DSS-induced colitis, and increased colonic TNF-α, Cxcl10, and Col2 α 1 mRNA expression.In situhybridization in TNBS-and DSS-exposed colons revealed increased miR-221-5p expression primarily in colonocytes.
  
  
  CONCLUSIONS
  Our results reveal a novel NK-1R-miR-221-5p-IL-6R network that protects from colitis. The use of miR-221-5p mimics may be a promising approach for colitis treatment.
authors.affiliation: Inflammatory Bowel Disease Center, David Geffen School of Medicine at UCLA.
authors.forename: Kai
authors.initials: K
authors.lastname: Fang
authors.affiliation: Inflammatory Bowel Disease Center, David Geffen School of Medicine at UCLA.
authors.forename: Aristea
authors.initials: A
authors.lastname: Sideri
authors.affiliation: Inflammatory Bowel Disease Center, David Geffen School of Medicine at UCLA.
authors.forename: Ivy Ka Man
authors.initials: IK
authors.lastname: Law
authors.affiliation: Inflammatory Bowel Disease Center, David Geffen School of Medicine at UCLA.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Bakirtzi
authors.affiliation: Center for Systems Biomedicine, Division of Digestive Diseases, David Geffen School of Medicine at UCLA.
authors.forename: Christos
authors.initials: C
authors.lastname: Polytarchou
authors.affiliation: Center for Systems Biomedicine, Division of Digestive Diseases, David Geffen School of Medicine at UCLA.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Iliopoulos
authors.affiliation: Inflammatory Bowel Disease Center, David Geffen School of Medicine at UCLA.
authors.forename: Charalabos
authors.initials: C
authors.lastname: Pothoulakis
keywords: SP; colitis; inflammation; microRNA