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All-trans retinoic acid-induced hypothalamus–pituitary–adrenal hyperactivity involves glucocorticoid receptor dysregulation
Clinical reports have highlighted a role for retinoids in the etiology of mood disorders. Although we had shown that recruitment of the nuclear receptor retinoic acid receptor-α (RAR-α) to corticotropin-releasing hormone (CRH) promoter is implicated in activation of the hypothalamus–pituitary–adrena...
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Published in: | Translational psychiatry 2013-12, Vol.3 (12), p.e336-e336 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Clinical reports have highlighted a role for retinoids in the etiology of mood disorders. Although we had shown that recruitment of the nuclear receptor retinoic acid receptor-α (RAR-α) to corticotropin-releasing hormone (CRH) promoter is implicated in activation of the hypothalamus–pituitary–adrenal (HPA) axis, further insight into how retinoids modulate HPA axis activity is lacking. Here we show that all-
trans
retinoic acid (RA)-induced HPA activation involves impairments in glucocorticoid receptor (GR) negative feedback. RA was applied to rats chronically through intracerebroventricular injection. A 19-day RA exposure induced potent HPA axis activation and typical depression-like behavior. Dexamethasone failed to suppress basal corticosterone (CORT) secretion, which is indicative of a disturbed GR negative feedback. In the hypothalamic paraventricular nucleus, increased CRH
+
and c-fos
+
cells were found while a negative R−2
+
/ER
+
correlation was present between the number of RAR-α
+
and GR
+
cells. This was paralleled by increased RAR-α and decreased GR protein expression in the hypothalamus. Additional
in vitro
studies confirmed that RA abolished GR-mediated glucocorticoid-induced suppression of CRH expression, indicating a negative cross-talk between RAR-α and GR signaling pathways. Finally, the above changes could be rapidly normalized by treatment with GR antagonist mifepristone. We conclude that in addition to the ‘classic’ RAR-α-mediated transcriptional control of CRH expression, disturbances in GR negative feedback constitute a novel pathway that underlies RA-induced HPA axis hyperactivity. The rapid normalization by mifepristone may be of potential clinical interest in this respect. |
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ISSN: | 2158-3188 2158-3188 |
DOI: | 10.1038/tp.2013.98 |