1. TCF-1-mediated Wnt signaling regulates Paneth cell innate immune defense effectors HD-5 and -6: implications for Crohn's disease.
- Author
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Beisner, Julia, Teltschik, Zora, Ostaff, Maureen J., Tiemessen, Machteld M., Staal, Frank J. T., Guoxing Wang, Gersemann, Michael, Perminow, Gori, Vatn, Morten H., Schwab, Matthias, Stange, Eduard F., and Wehkamp, Jan
- Subjects
CROHN'S disease ,INFLAMMATORY bowel diseases ,LABORATORY mice ,CATENINS ,JEJUNUM - Abstract
Wnt signaling regulates small intestinal stem cell maintenance and Paneth cell differentiation. In patients with ileal Crohn's disease (CD), a decrease of Paneth cell α-defensins has been observed that is partially caused by impaired TCF-4 and LRP6 function. Here we show reduced expression of the Wnt signaling effector TCF-1 (also known as TCF-7) in patients with ileal CD. Reporter gene assays and in vitro promoter binding analysis revealed that TCF-1 activates α-defensin HD-5 and HD-6 transcription in cooperation with β-catenin and that activation is mediated by three distinct TCF binding sites. EMSA analysis showed binding of TCF-1 to the respective motifs. In ileal CD patients, TCF-1 mRNA expression levels were significantly reduced. Moreover, we found specifically reduced expression of active TCF-1 mRNA isoforms. Tcf-1 knockout mice exhibited reduced cryptdin expression in the jejunum, which was not consistently seen at other small intestinal locations. Our data provide evidence that TCF-1-mediated Wnt signaling is disturbed in small intestinal CD, which might contribute to the observed barrier dysfunction in the disease. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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