Number Of Glucocorticoid Receptors Research Articles

Improving behavioral deficits induced by perinatal ethanol and stress exposure in adolescent male rat progeny via maternal melatonin treatment.

Early-life stressful situations and binge drinking have been thus far acknowledged as two burdensome conditions that potentially give rise to negative outcomes and then synergistically affect brain development. In this context, the hippocampus, with the greatest number of glucocorticoid receptors (GCRs) in the brain, is responsible for regulating negative responses to stress. Prolonged glucocorticoid (GC) exposure can accordingly cause oxidative stress (OS), leading to cognitive and emotional dysfunction. Against this background, melatonin, as a powerful antioxidant and hypothalamus-pituitary-adrenal (HPA) axis regulator, was administered in this study to ameliorate cognitive impairments induced by perinatal ethanol and stress exposure in adolescent male rat progeny. Wistar rat dams were exposed to ethanol (4 g/kg) and melatonin (10 mg/kg) from gestational day (GD) 6 to postnatal day (PND) 14 and then limited nesting material (LNS) from PND0 to PND14 individually or in combination. Maternal behavior was then investigated in mothers. Afterward, the plasma corticosterone (CORT) concentration, the OS marker, the corticotropin-releasing hormone receptor type 1 (CRHR1) expression, and the GCR and brain-derived neurotrophic factor (BDNF) levels were measured in the male pups. Moreover, behavioral tasks, including the elevated plus maze (EPM), the Morris water maze (MWM), the novel object recognition (NORT), and the object-location memory (OLM) tests were completed and assessed. The quantity and quality of maternal care significantly decreased in the mothers with dual exposure to ethanol and stress. The plasma CORT concentration in the progeny also dropped in the Ethanol + LNS group, but the risk-taking behavior elevated significantly. The ethanol and stress exposure further revealed a significant fall in the GCR and CRHR1 expression levels, compared with stress alone. The results of learning and memory tasks also indicated a significant reduction in spatial learning and memory among animals exposed to ethanol and stress. The BDNF mRNA levels correspondingly increased in the Ethanol + LNS group, compared with LNS alone. In the presence of ethanol and stress, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities correspondingly declined. On the other hand, the malondialdehyde (MDA) levels augmented in the hippocampus of the animals with ethanol and LNS dual exposure, as compared with the control group. Melatonin treatment (MT) thus improved nursing behaviors in dams, prevented OS, enhanced the CRHR1 and GCR expression, and reduced the BDNF levels to the similar ones in the control group. The animals in the Ethanol + LNS + MT group ultimately showed an ameliorated performance at behavioral tasks, including the memory and risk-taking behavior. It was concluded that MT could prevent stress response and memory impairments arising from dual exposure to ethanol and stress by inhibiting OS.

Stress aggravates imiquimod-induced psoriasiform inflammation by promoting M1 macrophage polarization

Psychological stress has long been considered to cause the aggravation and recurrence of psoriasis, but the underlying mechanism remains largely unknown. Here, we used a mouse model of restraint-induced stress and imiquimod (IMQ)-induced psoriasiform inflammation to investigate the crosstalk between stress and the skin immune system and their functions in the pathogenesis of psoriasis. We found that stress aggravated skin inflammation and elevated serum corticosterone (CORT) levels in mice. Stress also increased the number of macrophages and glucocorticoid receptor (GR) expression in IMQ-treated mouse skin. GR agonist CORT upregulated the phosphorylation of STAT1 to promote M1 macrophage polarization in vitro. Additionally, GR deletion in macrophages and pharmacologic inhibition of GR improved skin inflammation and reduced M1 macrophage polarization under stress. Taken together, these results indicate that stress aggravates psoriasiform inflammation by promoting CORT/GR signaling-induced M1 macrophage polarization, suggesting that blocking the GR signaling has great potential as an adjuvant treatment for psoriasis patients with chronic stress.

Long-Term Effects of Prenatal Severe Hypoxia on Central and Peripheral Components of the Glucocorticoid System in Rats

Introduction: Prenatal hypoxia is a risk factor for the development of numerous neurological disorders. It is known that the maternal stress response to hypoxia determines the epigenetic impairment of the perinatal expression of glucocorticoid receptors (GR) in the hippocampus of the progeny, but so far no detailed study of how this affects the functional state of the glucocorticoid system during further ontogenesis has been performed. Objective: The goal of the present study was to examine the long-term effects of the prenatal hypoxia on the functioning of the glucocorticoid system throughout life. Methods: Prenatal severe hypobaric hypoxia (PSH) was induced in the critical period of embryonic hippocampal formation on days 14–16 of gestation in a hypobaric chamber (180 Torr, 5% oxygen, 3 h). The activity of central (hippocampus) and peripheral (liver) components of the glucocorticoid system was assessed in 1-day-old (newborn), 2-week-old (juvenile), 3-month-old (adult), and 18-month-old (aged) male rats. Results: The PSH resulted in continuously elevated baseline corticosterone blood levels in the adult and aged rats. The chronic elevation of the corticosterone levels was accompanied by a progressive deficit of the GR expression in the liver, increased hepatic glycogen content, dysregulated glucose-6-phosphatase activity, and eventually hypoglycemia. Elevated corticosterone appears to result from the impairment of the mechanisms of glucocorticoid negative feedback since a substantial decrease in both the total number of GR and their nuclear localization was observed already in the hippocampus of newborn rat pups and persisted throughout life. Corresponding stable hippocampal downregulation of GR-dependent genes was observed as well. Suppression of the maternal glucocorticoid stress response to hypoxia by metyrapone injection to pregnant rats prior to each hypoxic challenge considerably reduced corticosterone over-response to hypoxia and prevented reduced hippocampal GR. Conclusions: Our findings demonstrate that in progeny a deficit of hippocampal GR resulting from maternal glucocorticoid response to hypoxia remains stable throughout life and is accompanied by severe disturbances of baseline glucocorticoid levels and its peripheral reception. Negative consequences of PSH can be prevented by injection with an inhibitor of corticosterone synthesis (metyrapone) to pregnant females undergoing hypoxia.

Роль гипоталамо-гипофизарно-адренокортикальной системы человека в адаптации к физическим нагрузкам

Regular physical activity, especially associated with the development of aerobic abilities, helps to improve the physical and mental health of a person. Increasing the level of fitness reduces the risk of overall mortality for both healthy people and people with chronic diseases. Exercise is accompanied by activation of the hypothalamic-pituitary-adrenocortical axis (HPA). The degree of its activation depends primarily on the intensity and duration of the load. Glucocorticoids of the adrenal glands which are hormones of the final link of the HPA, and their synthetic analogs can have a positive effect on the physical form of people. They adapt carbohydrate and fat metabolism to the energy needs of the body during exercise; have anti-inflammatory and immunosuppressive effects, protecting working muscles from damage. Adaptation to regular physical activity changes the reactivity of HPA most often in the direction of decreasing its susceptibility to negative feedback. It is also accompanied by changes in the sensitivity of tissues to glucocorticoids, which may be associated with the appearance of variations in the number and sensitivity of glucocorticoid receptors. The review describes the factors influencing the reaction of the HPA system in response to acute and chronic exercise, discusses the role of this system in adaptation of a person to physical activity. The great influence of individual characteristics of a person on the level of HPA reactivity during exercise is emphasized.

Reduced expression of the glucocorticoid receptor in the hippocampus of patients with drug-resistant temporal lobe epilepsy and comorbid depression.

ObjectiveDepressive disorders are common among about 50% of the patients with drug‐resistant temporal lobe epilepsy (TLE). The underlying etiology remains elusive, but hypothalamus‐pituitary‐adrenal (HPA) axis activation due to changes in glucocorticoid receptor (GR) protein expression could play an important role. Therefore, we set out to investigate expression of the GR in the hippocampus, an important brain region for HPA axis feedback, of patients with drug‐resistant TLE, with and without comorbid depression.MethodsGR expression was studied using immunohistochemistry on hippocampal sections from well‐characterized TLE patients with depression (TLE + D, n = 14) and without depression (TLE − D, n = 12) who underwent surgery for drug‐resistant epilepsy, as well as on hippocampal sections from autopsy control cases (n = 9). Video–electroencephalography (EEG), magnetic resonance imaging (MRI), and psychiatric and memory assessments were performed prior to surgery.ResultsAbundant GR immunoreactivity was present in dentate gyrus granule cells and CA1 pyramidal cells of controls. In contrast, neuronal GR expression was lower in patients with TLE, particularly in the TLE + D group. Quantitative analysis showed a smaller GR+ area in TLE + D as compared to TLE − D patients and controls. Furthermore, the ratio between the number of GR+/NeuN+ cells was lower in patients with TLE + D as compared to TLE − D and correlated negatively with the depression severity based on psychiatric history. The expression of the GR was also lower in glial cells of TLE + D compared to TLE − D patients and correlated negatively to the severity of depression.SignificanceReduced hippocampal GR expression may be involved in the etiology of depression in patients with TLE and could constitute a biological marker of depression in these patients.

Alteration of glucocorticoid receptors and exacerbation of inflammation during lytic cytomegalovirus infection in THP-1 cells.

Cytomegalovirus (CMV) infection is associated with glucocorticoid resistance in ulcerative colitis (UC) and may exacerbate the disease course. However, the underlying pathogenicity remains unclear. The aim of this study was to explore possible underlying mechanisms during CMV latency and lytic infection in the human mononuclear cell line THP‐1. Latent and activated CMV infection cell models were established. We performed real‐time PCR and western blotting to examine changes in glucocorticoid receptors (GRs) during CMV latency and activation. Pro‐inflammatory and anti‐inflammatory cytokines were detected by ELISA. After UV‐inactivated CMV infection, GRs and cytokines were also examined. The expression of GRs was elevated in the reactivation group. An increased ratio of GR β/α and phosphorylation of GRα in the CMV reactivation group may explain refractory response to steroids. During CMV lytic infection, pro‐inflammatory cytokines IL‐6 and TNF‐α increased remarkably and anti‐inflammatory cytokine IL‐5 decreased, which may exacerbate UC. GR and cytokines were unchanged in the UV‐inactivated CMV infection group. Changes in the number and function of GRs may account for glucocorticoid resistance in CMV reactivation. The imbalance of pro‐ and anti‐inflammatory cytokines may be related to severe inflammation.

Impact of Chronic Stress on the Spatial Learning and GR-PKAc-NF-κB Signaling in the Hippocampus and Cortex in Rats Following Cholinergic Depletion.

Studies have shown that the removal of the cholinergic innervation to the hippocampus induces dysfunction of the hypothalamic-pituitary-adrenocortical axis and decreases the number of glucocorticoid receptors (GRs). Subsequent studies have revealed that the loss of cholinergic input to the hippocampus reduces the expression of GRs and activates nuclear factor-kappa B (NF-κB) signaling through interactions with the cytoplasmic catalytic subunit of protein kinase A (PKAc). We examined the effects of chronic stress on cognitive status and GR-PKAc-NF-κB signaling in rats with a loss of cholinergic input to the hippocampus and cortex. Male Sprague-Dawley rats received 192 IgG-saporin injections to selectively eliminate cholinergic neurons in their basal forebrain. Two weeks later, rats were subjected to 1h of restraint stress per day for 14days. Rats subjected to both chronic stress and cholinergic depletion showed more severe memory impairments compared to those that received either treatment alone. The reduction in nuclear GR levels induced by cholinergic depletion was unaffected by chronic stress. The activation of NF-κB signaling in the hippocampus and the cerebral cortex induced by cholinergic depletion was augmented by chronic stress, resulting in the increased expression of pro-inflammatory markers, such as inducible nitric oxide synthase and cyclooxygenase-2. The activation of NF-κB induced by cholinergic depletion appears to be aggravated by chronic stress, and this might explain the increased susceptibility of patients with Alzheimer's disease to stress since activation of NF-κB is associated with stress.

Influence of Pre-reproductive Maternal Enrichment on Coping Response to Stress and Expression of c-Fos and Glucocorticoid Receptors in Adolescent Offspring

Environmental enrichment (EE) is an experimental setting broadly used for investigating the effects of complex social, cognitive, and sensorimotor stimulations on brain structure and function. Recent studies point out that parental EE experience, even occurring in the pre-reproductive phase, affects neural development and behavioral trajectories of the offspring. In the present study we investigated the influences of pre-reproductive EE of female rats on maternal behavior and adolescent male offspring's coping response to an inescapable stressful situation after chronic social isolation. For this purpose female Wistar rats were housed from weaning to breeding age in enriched or standard environments. Subsequently, all females were mated and housed in standard conditions until offspring weaning. On the first post partum day (ppd 1), mother-pup interactions in undisturbed conditions were recorded. Further, after weaning the male pups were reared for 2 weeks under social isolation or in standard conditions, and then submitted or not to a single-session Forced Swim Test (FST). Offspring's neuronal activation and plastic changes were identified by immunohistochemistry for c-Fos and glucocorticoid receptors (GRs), and assessed by using stereological analysis. The biochemical correlates were measured in the hippocampus, amygdala and cingulate cortex, structures involved in hypothalamic-pituitary-adrenocortical axis regulation. Enriched dams exhibited increased Crouching levels in comparison to standard reared dams. In the offspring of both kinds of dams, social isolation reduced body weight, decreased Immobility, and increased Swimming during FST. Moreover, isolated offspring of enriched dams exhibited higher levels of Climbing in comparison to controls. Interestingly, in the amygdala of both isolated and control offspring of enriched dams we found a lower number of c-Fos immunopositive cells in response to FST and a higher number of GRs in comparison to the offspring of standard dams. These results highlight the profound influence of a stressful condition, such as the social isolation, on the brain of adolescent rats, and underline intergenerational effects of maternal experiences in regulating the offspring response to stress.

Glucocorticoid receptor number and affinity differ between peripheral blood mononuclear cells and granulocytes in domestic pigs

The aim of the present study was to characterize the number and affinity of glucocorticoid receptors (GR) in peripheral blood mononuclear cells (PBMC) and granulocytes of domestic pigs because glucocorticoid signaling is considered important for animal health and welfare. To investigate GR binding characteristics in intact porcine immune cells, blood samples of 6 castrated male pigs were collected via indwelling vein catheters. Porcine PBMC and granulocytes were isolated using two-layer density gradients, followed by radioligand binding assays to determine the number of GR sites per cell and the dissociation constant Kd as a measure for GR binding affinity. The present study revealed a greater number of GR sites per cell (P = 0.039) in PBMC (mean ± SEM: 1,953 ± 207 sites/cell) compared to granulocytes (1,561 ± 159 sites/cell) in domestic pigs. Furthermore, porcine PBMC had a higher GR binding affinity than porcine granulocytes (P = 0.003) as the dissociation constant Kd of PBMC (1.8 ± 0.2 nM) was lower than that of granulocytes (3.5 ± 0.4 nM). Our results point to differences in underlying mechanisms of glucocorticoid signaling in different porcine leukocyte populations.

Effects of caloric restriction and low glycemic index diets associated with metformin on glucose metabolism and cortisol response in overweight/obese subjects: a case series study.

BackgroundTo determine whether cortisol secretion and glucocorticoid receptors in lymphocytes and monocytes are altered in patients with impaired glucose tolerance, and whether treatment with a hypocaloric diet and metformin could interfere with these aspects.MethodsThis is an analytical, interventional, case series study. Patients with impaired glucose tolerance were included. They received 500 mg of metformin twice daily and followed a low glycemic index diet for 16 weeks. Cortisol levels were assessed at 8:00 A.M. before and after use of 0.25 mg of dexamethasone at 11:00 P.M. the day before.ResultsSixteen subjects (9 men) were included. Normal basal levels of cortisol and adequate responses to the low dose of dexamethasone were observed before and after treatment. There was no significant correlation between the parameters evaluated and cortisol levels. Nevertheless, there was a strong correlation between the number of glucocorticoid receptors, BMI (r = 0.88; p = 0.02), and insulin AUC (r = 0.94; p = 0.005) before treatment; after treatment, all these associations ceased to exist.ConclusionThe cortisol secretion remained normal in the group of patients with impaired glucose tolerance. Treatment with metformin and diet did not change this condition. However, glucocorticoid receptor number had a strong correlation with insulin, due to insulin resistance, but this characteristic was lost after treatment.

Modulation of central glucocorticoid receptors in short- and long-term experimental hyperthyroidism.

Hyperthyroidism is associated with a significant increase in circulating glucocorticoid levels and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. The aim of this study was to examine whether the HPA axis hyperactivity observed in hyperthyroidism may be explained by a disturbed feedback inhibition of endogenous glucocorticoids through two specific intracellular receptors in the brain: the high affinity mineralocorticoid receptor (MR) and the lower affinity glucocorticoid receptor (GR). Cytosolic receptor binding and gene expression was assessed in rats with short (7 days) and long standing (60 days) eu- and hyperthyroidism. Glucocorticoid receptor number and binding affinity (Kd) in the hippocampus were measured using [(3)H2]-dexamethasone radioreceptor assay. In situ hybridization was employed to examine the effects of hyperthyroidism on the GR and MR mRNA levels in the hippocampus and the pituitary. Both short- and long-term hyperthyroid rats showed pronounced reduction in the concentration of cytosolic GR in the hippocampus, without changes in binding affinity or changes in GR expression. In contrast, GR mRNA in the pituitary increased after 7 days and decreased after 60 days of thyroxin treatment. MR mRNA was moderately affected. Hyperthyroidism is associated with significant decreases in hippocampal GR levels supporting the hypothesis that hyperactivity of the HPA axis observed in experimentally induced hyperthyroidism may be attributed, at least in part, to decreased negative feedback at the level of the hippocampus. These findings further support the notion that a central locus is principally responsible for the hyperactivity of the HPA axis observed in hyperthyroidism.

The influence of combined oral contraceptives containing drospirenone on hypothalamic-pituitary-adrenocortical axis activity and glucocorticoid receptor expression and function in women with polycystic ovary syndrome.

Most women with PCOS have increased adrenal androgen production, enhanced peripheral metabolism of cortisol and elevation in urinary excretion of its metabolites. Increased cortisol clearance in PCOS is followed by a compensatory overdrive of the hypothalamic-pituitary-adrenocortical (HPA) axis. We hypothesized that oral contraceptives containing ethinylestradiol and drospirenone (EE-DRSP) could modulate glucocorticoid receptor (GR) expression and function and thus affect HPA axis activity in PCOS patients. We analyzed 12 women with PCOS (age 24.17±4.88 years; body mass index 22.05±3.97 kg/m²) treated for 12 months with EE-DRSP and 20 BMI matched controls. In all subjects testosterone, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), cortisol (basal and after dexamethasone), concentrations of GR protein, phospo-GR211 protein, number of GR per cell (B(max) and its equilibrium dissociation constant (K(D)) were measured. Before treatment, increased concentrations of testosterone and DHEAS (p<0.001, respectively), unaltered basal cortisol and an increased sensitivity (p<0.05) of the HPA axis to dexamethasone were observed in PCOS women in comparison to controls. After treatment, testosterone (p<0.01), DHEAS (p<0.05) and cortisol suppression after dexamethasone (p<0.01) were decreased in PCOS women. There were no changes in GR protein concentration, GR phosphorylation nor in the receptor functional parameters B(max) and K(D) in women with PCOS before and after the therapy, and in comparison to controls. Prolonged treatment with EE-DRSP in PCOS women decreased serum androgens and increased cortisol in the presence of decreased sensitivity of the HPA axis and did not exert changes in GR expression and function.

Folliculo-stellate cells – Potential mediators of the inflammaging-induced hyperactivity of the hypothalamic–pituitary–adrenal axis in healthy elderly individuals

Some evidence has suggested that, with age, the hypothalamic–pituitary–adrenal (HPA) axis becomes less resilient, leading to higher glucocorticoids nocturnal levels and a flattening of the circadian profiles. Such age-related changes in the activity of the HPA axis has overexposed the brain and peripheral organs to the effects of the glucocorticoids, increasing the morbidity and mortality rates of the elderly. Debate among scientists regarding the contributions of HPA axis age-related changes of impaired feedback regulation vs. direct overactivation persists. Supporters of impaired feedback regulation assumed that this effect might be the consequence of the hippocampal age-related neuronal loss and the reduction of the number of mineralocorticoid and glucocorticoid receptors. On the other hand, healthy elderly individuals are characterized by an increase of proinflammatory cytokines, including IL-1, IL-6, and TNF-α, and the development of a chronic low-grade inflammatory state, known as inflammaging. Cytokines central to inflammaging send signals to the brain, activate HPA axis, and, by increased cortisol secretion, down-regulate inflammaging in a process known as anti-inflammaging. Even as these cytokines act at the level of the hypothalamic paraventricular nucleus, they are hampered by the intact blood–brain barrier. Further, the corticotropes in the anterior pituitary do not express cytokine receptors, and the density of folliculo-stellate cells generally increases with age. Therefore, we assumed that folliculo-stellate cells were the target structures through which the elevated levels of cytokines, as a part of the inflammaging phenomenon, would cause the overactivation of the HPA axis in healthy elderly individuals. Folliculo-stellate cells are non-endocrine cells that were originally considered to act as supporting cells for the endocrine cells. Despite the fact that FS cells do not produce any of the established hormones of the anterior pituitary, they secrete paracrine agents that act locally to modulate pituitary responses to hypothalamic and peripheral signals. There is evidence of cytokines characteristically involved in inflammaging. For example, IL-1 and TNF-α are thought to stimulate folliculo-stellate cells to release various paracrine agents, including IL-6, IL-11, leukemia inhibitory factor, and macrophage migration inhibitory factor. Through different mechanisms, these agents induce ACTH release by corticotropes. Therefore, it can be concluded that folliculo-stellate cells may act as potent mediators of the age-related HPA axis hyperactivity induced by cytokines characteristic of the inflammaging phenomenon in healthy elderly individuals.

Mineralocorticoid receptor and heat shock protein expression levels in peripheral lymphocytes from war trauma-exposed men with and without PTSD

Alterations in the number and functional status of mineralocorticoid (MR) and glucocorticoid receptors (GR) may contribute to vulnerability to posttraumatic stress disorder (PTSD). Corticosteroid receptors are chaperoned by heat shock proteins Hsp90 and Hsp70. We examined relations between corticosteroid receptor and heat shock protein expression levels, and related them with war trauma exposure, PTSD and resilience to PTSD. Relative levels of MR, Hsp90 and Hsp70 were determined by immunoblotting in lymphocytes from war trauma-exposed men with current PTSD (current PTSD group, n=113), with life-time PTSD (life-time PTSD group, n=61) and without PTSD (trauma control group, n=88), and from non-traumatized healthy controls (healthy control group, n=85). Between-group differences in MR, Hsp90 and Hsp70 levels and in MR/GR ratio were not observed. The level of MR was correlated with both Hsp90 and Hsp70 levels in trauma control and healthy control groups. On the other hand, GR level was correlated only with Hsp90 level, and this correlation was evident in current PTSD and trauma control groups. In conclusion, PTSD and exposure to trauma are not related to changes in lymphocyte MR, Hsp90 or Hsp70 levels, but may be associated with disturbances in corticosteroid receptors interaction with heat shock proteins.

112. The pig (Sus scrofa) as a suitable non-rodent model system: Enabling the quantification of number and affinity of glucocorticoid receptors in porcine leukocytes

Glucocorticoids, being one central link between the neuroendocrine and the immune system, act on leukocytes directly via endogenous glucocorticoid receptors (GR). Consequently, the number and affinity of these receptor sites in immune cells is crucial for the sensitivity towards glucocorticoids and thus their immune-modulating effects. Although the pig is considered as a suitable model organism for studying the immune system, there is no research concerning GR in porcine leukocytes so far and methods allowing their quantification are currently missing. Therefore, this study aimed at the establishment of a quantification method of GR number and affinity in porcine leukocytes. A 3 H-dexamethasone-based receptor-binding assay adapted for processing in 96-well microtiter plates allowing quantitative analysis of GR in porcine leukocytes was accomplished. A detection limit of 1.5 × 10 8 total receptor sites and a quantification limit of 7.6e8 total receptor sites was found. Evaluation of the intra-assay-precision for quantification of the GR number and affinity showed a coefficient of variation of 2.5% and 3.0%, respectively. A range of 1500–2900 GR/cell showing affinities of K d = 1.4–3.1 nM were found for porcine PBMC, thereby closely corresponding to results for human PBMC. Comparison of PBMC and granulocytes revealed similar numbers of GR/cell on both leukocyte types but lower GR affinities in granulocytes, which resembles findings in goats. In summary, the established binding assay allows reliable quantification of GR number and affinity in porcine leukocytes.

The ontogenetic pattern of the expression of glucocorticoid receptors and the transcription factor NGFI-A in the hippocampus of male rats after prenatal stress

Using the immunohistochemical method, we studied the expression of glucocorticoid receptors (GRs) in the hippocampus during the postnatal period of development of male rats that were born to dams that were subjected to immobilization stress from the 15th to 19th day of pregnancy. In addition, we used Western blotting to study changes in the expression of the transcription factor NGFI-A in the hippocampus of prenatally stressed animals. We found that prenatal stress induces a considerable decrease in the number of GR-positive cells in the CA1 area of the hippocampus and dentate gyrus during the 1st week of life, an increase in their number and the number of strongly immunopositive cells during the 2nd week, and a decrease in the number of GR-expressing cells in the 3rd week of life. The expression of NGFI-A in the hip-pocampus of prenatally stressed males increased during the 1st and 2nd weeks of life but did not change during the 3rd week as compared to the control animals. We conclude that the destructive effects of prenatal stress on the developing hippocampus may be determined by alteration of the number of GRs in the early postnatal period, whereas induction of NGFI-A in the hippocampus of prenatally stressed males in the early neonatal period possibly has an adaptive character.

Corticotropin-Releasing Hormone Affects Short Immobilization Stress-Induced Changes in Lung Cytosolic and Membrane Glucocorticoid Binding Sites

Glucocorticoids act via glucocorticoid receptors (GR), typically localized in the cytosol (cGR). Rapid action is probably mediated via membrane receptors (mGR). In corticotropin-releasing hormone knockouts (CRH-KO), basal plasma glucocorticoid levels do differ from wild type levels (WT), but are approximately ten times lower during exposure to immobilization stress (IMMO) in comparison to WT. We tested the following hypotheses: (1) the mice lung tissue GR basal numbers would not be changed in CRH-KO (because of similar glucocorticoid levels), (2) the number of GR would be changed in WT but not in KO during short (30, 90, and 120min) IMMO (because of higher increase of glucocorticoid levels in WT). The basal levels of cGR were not changed in CRH-KO (compared to WT), while mGR were significantly lower (62%) in CRH-KO. In WT, there was the only decrease (to 32%) in cGR after 120min when we also found an increase in mGR in WT (to 201%). In CRH-KO, IMMO caused gradual decrease in cGR (to 52% after 30min, to 46% after 90min, and to 32% after 120min). In CRH-KO, the only increase in mGR appeared already at 30min of IMMO. These data suggest, on the contrary to our hypotheses, that CRH-KO are more susceptible to GR changes in early phases of stress.

Quantifying the number and affinity of glucocorticoid receptors in porcine peripheral blood mononuclear cells – Establishment of a ligand binding assay

Glucocorticoids display a central link between the neuroendocrine and the immune system. As they act on leukocytes directly via endogenous glucocorticoid receptors (GR), both the number and affinity of these receptor sites are crucial for the immune-modulating effects of glucocorticoids. Although the pig is considered as suitable model organism for studying the immune system, there is no research concerning GR in porcine leukocytes so far. Moreover, methods allowing their quantification are currently missing. Therefore, this study aimed at the establishment of a method for the quantification of GR number and affinity in porcine peripheral blood mononuclear cells (PBMC). A 3H-dexamethasone-based receptor-binding assay adapted for processing in 96-well microtiter plates allowing quantitative analysis of GR in porcine PBMC was established. By calculating the signal to noise ratio using 106 PBMC/well a detection limit of 1.5 × 108 total receptor sites and a quantification limit of 7.6 × 108 total receptor sites were found. Evaluation of the intra-assay-precision for quantification of GR number and affinity showed a coefficient of variation of 2.5% and 3.0%, respectively. A range of 1500–2900 GR/cell showing affinities of Kd = 1.4–3.1 nM were found for porcine PBMC (n = 15), thereby closely corresponding to results for human PBMC. Comparing fresh and frozen PBMC probes revealed that PBMC stored at −80 °C showed a 13.8% increase in GR number/cell, most probably resulting from a concomitant shift in monocyte to lymphocyte ratios in the frozen probes due to different cell viabilities. In summary, the established binding assay reliably allows quantification of GR number and affinity in porcine PBMC.

How Does Lymphocyte Glucocorticoid Receptor Expression and Salivary Cortisol Relate to Trauma Exposure and Posttraumatic Stress Disorder?

How Does Lymphocyte Glucocorticoid Receptor Expression and Salivary Cortisol Relate to Trauma Exposure and Posttraumatic Stress Disorder? Hypothalamus-pituitary-adrenal axis functioning and glucocorticoid receptor number on lymphocyte subsets were investigated in patients with posttraumatic stress disorder related to type I trauma, trauma-exposed subjects without posttraumatic stress disorder and trauma-unexposed control subjects (n=13 per group) applying a detailed endocrinological assessment. Salivary cortisol profiles were obtained, first, as diurnal baseline cortisol (unstimulated), and second, after dexamethasone administration (stimulated cortisol) to investigate the negative feedback inhibition of the hypothalamus-pituitary-adrenal axis. For further assessment of glucocorticoid receptor binding, glucocorticoid receptor counts on lymphocytes were obtained from blood samples.

Predicting PTSD: Pre-existing vulnerabilities in glucocorticoid-signaling and implications for preventive interventions

Posttraumatic stress disorder (PTSD) is an anxiety disorder that may develop in response to a traumatic event. Approximately 10% of trauma-exposed individuals subsequently develop PTSD. It is hypothesized that the development of PTSD is associated with biological vulnerability factors, which are already present prior to the onset of symptoms. In this review we present an overview of currently identified vulnerability factors in the glucocorticoid (GC) signaling pathway for the development of PTSD. In addition, the implications of the identified vulnerability factors for potential preventive intervention strategies, including glucocorticoid receptor (GR) agonists and oxytocin, are discussed. Summarized, the findings of these studies indicate that individuals vulnerable for development of PTSD have dysregulations on various levels of the GC-signaling cascade: i.e. low levels of circulating levels of cortisol shortly after trauma, high GR number in peripheral blood mononuclear cells (PBMCs), high GILZ mRNA expression and low FKBP5 expression in PBMCs prior to trauma, and high sensitivity of T-cells for regulation by GCs prior to trauma. Furthermore, single nucleotide polymorphisms in the GR and FKBP5 genes have been found to be associated with increased risk for PTSD. Collectively, the identified vulnerability factors tentatively suggest that the development of PTSD may be preceded by a high sensitivity of various cells for regulation by GCs. The identification of these vulnerability factors may ultimately aid selective targeting of preventive interventions towards individuals at risk for PTSD. In addition, the identification of these vulnerability factors may eventually result in new preventive pharmacological strategies for PTSD.