Expression profiling of Wnt family of genes in normal and inflammatory bowel disease primary human intestinal myofibroblasts and normal human colonic crypt epithelial cells.
BACKGROUND
Wnt signaling regulates intestinal epithelial stem cell function. Wnt ligands bind Frizzled (Fz) receptors and low-density lipoprotein-receptor-related protein (LRP) 5 and 6. Secreted Frizzled-related protein (SFRP) and Dickkopf families inhibit Wnt signaling. Our aim was to study expression of Wnt family of genes in isolated intestinal myofibroblasts and crypt epithelial cells.


METHODS
Myofibroblasts were isolated from normal colonic and small intestinal mucosal samples and those affected by ulcerative colitis (UC) and Crohn's disease. Expression of the Wnt family of genes was studied by polymerase chain reaction (PCR) array. Epithelial proliferation was studied using IEC-6 cells.


RESULTS
Most of the myofibroblast isolates expressed Wnt2, Wnt5A, Wnt5B, Fzd1, Fzd2, Fzd4, Fzd6, Fzd7, Fzd8, LRP6, Dickkopf1, and SFRP1. Compared to myofibroblasts isolated from normal colonic mucosal samples, real-time reverse transcription-PCR studies (using additional isolates) showed significantly reduced expression of SFRP1 in UC myofibroblasts (3.34-fold reduction, P < 0.01). Recombinant SFRP1 inhibited proliferation of IEC-6 epithelial cells. In colonic crypt epithelial cells, expression of Wnt ligands and their inhibitors was generally either absent or very weak. By contrast, all the crypt epithelial preparations expressed Fzd1, Fzd5, Fzd7, Fzd8, and LRP6.


CONCLUSIONS
Human intestinal myofibroblasts expressed a number of Wnt ligands, their receptors, and inhibitors. In contrast, colonic crypt epithelial cells predominantly expressed Wnt receptors. Compared to myofibroblasts isolated from normal colonic mucosa, those affected by UC showed significantly reduced expression of SFRP1. Since reduced SFRP1 expression has been associated with malignancy, low myofibroblast expression of this Wnt inhibitor may be implicated in increased risk of cancer in UC.
Hughes
K R
KR
Institute of Infection, Immunity and Inflammation, University of Nottingham, Nottingham, UK.
Sablitzky
F
F
Mahida
Y R
YR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D058628:Myofibroblasts / Q000378:metabolism* / Q000473:pathology; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051153:Wnt Proteins / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult; D000094742:Secreted Frizzled-Related Proteins
D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D051153:Wnt Proteins; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins