Journal of Endocrinology (2009) 202, 87-97
DOI: 10.1677/JOE-08-0509
© 2009 Society for Endocrinology
Acute or chronic stress induce cell compartment-specific phosphorylation of glucocorticoid receptor and alter its transcriptional activity in Wistar rat brain
Miroslav Adzic,
Jelena Djordjevic,
Ana Djordjevic,
Ana Niciforovic,
Constantinos Demonacos1,
Marija Radojcic and
Marija Krstic-Demonacos2
Laboratory of Molecular Biology and Endocrinology, VINCA Institute of Nuclear Sciences, PO Box-522-MBE090, 11001 Belgrade, Serbia
1 School of Pharmacy
2 Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT England, UK
(Correspondence should be addressed to M Krstic-Demonacos; Email: m.k.demonacos{at}manchester.ac.uk)
This is an Open Access article distributed under the terms of the Society for Endocrinology's Re-use Licence which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Chronic stress and impaired glucocorticoid receptor (GR) feedback are important factors for the compromised hypothalamic–pituitary–adrenal (HPA) axis activity. We investigated the effects of chronic 21 day isolation of Wistar rats on the extrinsic negative feedback part of HPA axis: hippocampus (HIPPO) and prefrontal cortex (PFC). In addition to serum corticosterone (CORT), we followed GR subcellular localization, GR phosphorylation at serine 232 and serine 246, expression of GR regulated genes: GR, CRF and brain-derived neurotropic factor (BDNF), and activity of c-Jun N-terminal kinase (JNK) and Cdk5 kinases that phosphorylate GR. These parameters were also determined in animals subjected to acute 30 min immobilization, which was taken as normal adaptive response to stress. In isolated animals, we found decreased CORT, whereas in animals exposed to acute immobilization, CORT was markedly increased. Even though the GR was predominantly localized in the nucleus of HIPPO and PFC in acute, but not in chronic stress, the expression of GR, CRF, and BDNF genes was similarly regulated under both acute and chronic stresses. Thus, the transcriptional activity of GR under chronic isolation did not seem to be exclusively dependent on high serum CORT levels nor on the subcellular location of the GR protein. Rather, it resulted from the increased Cdk5 activation and phosphorylation of the nuclear GR at serine 232 and the decreased JNK activity reflected in decreased phosphorylation of the nuclear GR at serine 246. Our study suggests that this nuclear isoform of hippocampal and cortical GR may be related to hypocorticism i.e. HPA axis hypoactivity under chronic isolation stress.
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Copyright © 2009 by the Society for Endocrinology.