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Separating transrepression and transactivation: a distressing divorce for the glucocorticoid receptor?
1Department of Cell Biology and Anatomy, Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada. rnewton@ucalgary.ca
Molecular Pharmacology
|July 12, 2007
Summary
Glucocorticoids combat inflammation but cause side effects via gene transactivation. Their anti-inflammatory effects rely on transrepression and post-transcriptional mechanisms, crucial for developing safer drugs.
Area of Science:
- Pharmacology and Molecular Biology
- Immunology and Inflammation Research
Background:
- Glucocorticoids are potent anti-inflammatory agents used across various diseases.
- Clinical efficacy is limited by side effects, often linked to glucocorticoid receptor (GR) gene transactivation.
- Anti-inflammatory actions are primarily attributed to GR-mediated transrepression of pro-inflammatory genes.
Purpose of the Study:
- To review the evidence supporting the importance of post-transcriptional mechanisms in glucocorticoid anti-inflammatory actions.
- To highlight the critical role of mechanistically distinct gene expression in repressing inflammatory pathways.
- To emphasize the need for careful development of novel GR ligands that separate transrepression from transactivation.
Main Methods:
- Literature review focusing on glucocorticoid receptor (GR) function.
- Analysis of transcriptional (transactivation and transrepression) and post-transcriptional mechanisms.
- Evaluation of evidence for distinct forms of GR-inducible gene expression.
Main Results:
- Post-transcriptional mechanisms significantly contribute to the anti-inflammatory effects of glucocorticoids.
- Glucocorticoid-inducible gene expression operates through mechanistically distinct pathways critical for anti-inflammation.
- Repression of inflammatory signaling and gene expression occurs at multiple levels.
Conclusions:
- Post-transcriptional regulation is a key component of glucocorticoid anti-inflammatory activity.
- Understanding distinct gene expression mechanisms is vital for therapeutic development.
- Novel GR ligands must preserve anti-inflammatory effectiveness while minimizing transactivation-associated side effects.
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