The role of phosphorylated glucocorticoid receptor in mitochondrial functions and apoptotic signalling in brain tissue of stressed Wistar rats.
Mitochondrial dysfunction is increasingly recognized as a key component in compromised neuroendocrine stress response and, among other etiological causes, it may also involve action of glucocorticoid hormones. In the current study we followed glucocorticoid receptor and identified its mitochondrial phosphoisophorms in hippocampus and prefrontal brain cortex of Wistar male rats subjected to acute, chronic and combined neuroendocrine stresses. In both brain structures chronic social isolation caused marked increase in mitochondrial glucocorticoid receptor that was preferentially phosphorylated at serine 232 compared to serine 246 or serine 171. This increase corresponded with the decreased expression of mitochondrially encoded cytochrome oxidase subunits 1 and 3 in hippocampus, and with their increased expression in prefrontal brain cortex. Prefrontal brain cortex appeared to be more sensitive to chronic stress, since it exibited higher levels of mitochondrial Bax and cytoplasmic Bcl2 compared to hippocampus. Chronic stress also altered the response of both brain structures to subsequent acute stress according to the studied parameters. Therefore, prolonged social isolation may cause susceptibility to mitochondria triggered proapototic signalling, which at least in part may be mediated by the glucocorticoid receptor dependent mechanism.
Laboratory of Molecular Biology and Endocrinology, VINCA Institute of Nuclear Sciences, P.O. Box-522-MBE090, 11001 Belgrade, Serbia. miraz@vinca.rs
Miroslav
M
Adzic
Ana
A
Djordjevic
Constantinos
C
Demonacos
Marija
M
Krstic-Demonacos
Marija B
MB
Radojcic
D000818:Animals; D017209:Apoptosis; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology*; D003345:Corticosterone / Q000097:blood; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D053938:DNA Fragmentation; D015971:Gene Expression Regulation, Enzymologic; D006624:Hippocampus / Q000201:enzymology / Q000503:physiopathology; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D017397:Prefrontal Cortex / Q000201:enzymology / Q000503:physiopathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D015398:Signal Transduction; D013312:Stress, Physiological
D008565:Membrane Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011965:Receptors, Glucocorticoid; D010768:Phosphoserine; D051545:Cyclooxygenase 1; C496513:Ptgs1 protein, rat; D003345:Corticosterone