Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Subscribe

Sci. Signal., 25 February 2014
Vol. 7, Issue 314, p. ra20
[DOI: 10.1126/scisignal.2004786]

RESEARCH ARTICLES

Tumor Necrosis Factor Suppresses NR5A2 Activity and Intestinal Glucocorticoid Synthesis to Sustain Chronic Colitis

Sheng-Chieh Huang1,2, Cheng-tse Lee1,3, and Bon-chu Chung1,2,3*

1 Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan.
2 Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan.
3 Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan.

Abstract: Intestinal crypt epithelial cells synthesize glucocorticoids, steroid hormones that protect against inflammatory bowel disease. To investigate how intestinal glucocorticoids are regulated during chronic inflammation, we induced chronic colitis in mice by exposing them to the chemical dextran sulfate sodium (DSS). We found that intestinal glucocorticoid secretion and expression of the genes Cyp11a1 and Cyp11b1 (which encode enzymes that synthesize glucocorticoids) were initially stimulated, but declined during the chronic phase, whereas tumor necrosis factor (TNF) and inflammatory cytokines secreted by T helper type 1 (TH1) and TH17 cells continuously increased in abundance in the inflamed colon. This suggested that inadequate intestinal glucocorticoid synthesis is a feature of chronic intestinal inflammation. We screened for cytokines that regulated intestinal glucocorticoid synthesis and found that TNF suppressed corticosterone secretion and Cyp11a1 and Cyp11b1 expression in an intestinal crypt epithelial cell line. TNF suppressed steroidogenesis by activating the transcription factors c-Jun and nuclear factor {kappa}B (NF-{kappa}B), which both interacted with the transcription factor NR5A2 and repressed Cyp11a1 reporter activity. This repression was relieved by expression of a dominant-negative form of c-Jun amino-terminal kinase 1 (JNK1), inhibitor of NF-{kappa}B, or by a JNK inhibitor. Furthermore, the dominant-negative TNF inhibitor XPro1595 inhibited c-Jun and NF-{kappa}B activation in mice, restored intestinal Cyp11a1 and Cyp11b1 expression, reduced colonic cell death, and rescued chronic colitis caused by DSS. Thus, during chronic colitis, TNF suppresses intestinal steroidogenic gene expression by inhibiting the activity of NR5A2, thus decreasing glucocorticoid synthesis and sustaining chronic inflammation.

* Corresponding author. E-mail: mbchung{at}sinica.edu.tw

Citation: S.-C. Huang, C.-t. Lee, B.-c. Chung, Tumor Necrosis Factor Suppresses NR5A2 Activity and Intestinal Glucocorticoid Synthesis to Sustain Chronic Colitis. Sci. Signal. 7, ra20 (2014).

Read the Full Text



To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882