MicroRNAs are differentially expressed in ulcerative colitis and alter expression of macrophage inflammatory peptide-2 alpha.
OBJECTIVE
Chronic inflammatory bowel diseases such as ulcerative colitis (UC) are associated with differential expression of genes involved in inflammation and tissue remodeling. MicroRNAs (miRNAs), which direct mRNA degradation and translational inhibition, influence a number of disease processes. We examined whether miRNAs are differentially expressed in UC tissues and are associated with expression of genes that regulate inflammation.


METHODS
miRNA expression was assessed in patients with active UC, inactive UC, Crohn's disease, irritable bowel syndrome, infectious colitis, and microscopic colitis, as well as in healthy subjects by microarray, quantitative reverse transcription-polymerase chain reaction and in situ hybridization analyses. Colonic epithelial cell (HT29) expression of miRNAs was assessed. Regulation of gene expression by miRNAs was assessed by luciferase reporter construct assays and transfection of specific miRNA mimics.


RESULTS
Active UC was associated with the differential expression of 11 miRNAs; 3 were significantly decreased and 8 were significantly increased in UC tissues. In situ hybridization analysis indicated that miR-192, an miRNA with decreased expression in active UC, was predominantly localized to colonic epithelial cells. Macrophage inflammatory peptide (MIP)-2 alpha, a chemokine expressed by epithelial cells, was identified as a target of miR-192. In colon epithelial cells, induction of MIP-2 alpha expression by tumor necrosis factor-alpha was accompanied by a concomitant reduction in miR-192 expression and miR-192 was observed to regulate the expression of MIP-2 alpha.


CONCLUSIONS
These findings expand the known roles of miRNAs, indicating that tissues from patients with UC, and possibly other chronic inflammatory diseases, have altered miRNA expression patterns. These findings also demonstrate that miRNAs regulate colonic epithelial cell-derived chemokine expression.
The Harvey M. and Lyn P. Meyerhoff Inflammatory Bowel Disease Center, Department of Medicine, Division of Gastroenterology, The Johns Hopkins University Medical Institutions, Baltimore, Maryland 21205-2195, USA.
Feng
F
Wu
Michelle
M
Zikusoka
Anil
A
Trindade
Themistocles
T
Dassopoulos
Mary L
ML
Harris
Theodore M
TM
Bayless
Steven R
SR
Brant
Shukti
S
Chakravarti
John H
JH
Kwon
D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D054426:Chemokine CXCL2 / Q000096:biosynthesis / Q000235:genetics*; D003093:Colitis, Ulcerative / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020895:Enterocytes / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046509:Tissue Culture Techniques; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D055815:Young Adult
D054426:Chemokine CXCL2; D035683:MicroRNAs; D014409:Tumor Necrosis Factor-alpha