Glucocorticoid Receptor mRNA Expression Research Articles

The possibly role of GnIH in stress and gut dysfunction in chicken

Stress is known to disrupt the intestinal barrier and induce intestinal dysfunction. A critical role for gonadotropin inhibitory hormone (GnIH) in stress has emerged. However, whether GnIH mediates stress-induced intestinal dysfunction remains unknown. The present study explored this question through in vivo and in vitro experiments in hens. Our in vivo experiments showed that continuous intraperitoneal injection of GnIH not only significantly increased the concentration of stress hormones in serum, but also significantly elevated the mRNA expression of glucocorticoid receptor (GR) in the duodenum and jejunum. Moreover, morphological and molecular analyses revealed that GnIH disrupted the physical and chemical barriers of the intestine and dramatically increased inflammatory factor levels in the intestine and serum of hens. Interestingly, the microbiomics results showed that GnIH altered the structure and composition of the gut flora in the cecum, revealing an increased abundance of harmful intestinal bacteria such as Desulfovibrionaceae. Similar results were found in in vitro studies in which the GnIH-induced intestinal mucosal barrier was disrupted, and inflammation increased in jejunal explants, although no significant difference was found in the expression of GR between the control and GnIH groups. Our results demonstrated that GnIH not only directly damaged intestinal barriers and elevated intestinal inflammation but also mediated stress and microflora imbalance-induced intestinal function disorder, suggesting that GnIH is a potential therapeutic target for gut dysfunction, stress-induced intestinal function disorder, and inflammatory bowel disease in animals and humans.

Glucocorticoid treatment influences prostate cancer cell growth and the tumor microenvironment via altered glucocorticoid receptor signaling in prostate fibroblasts

Despite significant therapeutic advances in recent years, treatment of metastatic prostate cancer (PCa) remains palliative, owing to the inevitable occurrence of drug resistance. There is increasing evidence that epithelial glucocorticoid receptor (GR) signaling and changes in the tumor-microenvironment (TME) play important roles in this process. Since glucocorticoids (GCs) are used as concomitant medications in the course of PCa treatment, it is essential to investigate the impact of GCs on stromal GR signaling in the TME. Therefore, general GR mRNA and protein expression was assessed in radical prostatectomy specimens and metastatic lesions. Elevated stromal GR signaling after GC treatment resulted in altered GR-target gene, soluble protein expression, and in a morphology change of immortalized and primary isolated cancer-associated fibroblasts (CAFs). Subsequently, these changes affected proliferation, colony formation, and 3D-spheroid growth of multiple epithelial PCa cell models. Altered expression of extra-cellular matrix (ECM) and adhesion-related proteins led to an ECM remodeling. Notably, androgen receptor pathway inhibitor treatments did not affect CAF viability. Our findings demonstrate that GC-mediated elevated GR signaling has a major impact on the CAF secretome and the ECM architecture. GC-treated fibroblasts significantly influence epithelial tumor cell growth and must be considered in future therapeutic strategies.

Acute restraint stress rapidly impacts reproductive neuroendocrinology and downstream gonad function in big brown bats (Eptesicus fuscus).

Animals face unpredictable challenges that require rapid, facultative physiological reactions to support survival but may compromise reproduction. Bats have a long-standing reputation for being highly sensitive to stressors, with sensitivity and resilience varying both within and among species, yet little is known about how stress affects the signaling that regulates reproductive physiology. Here, we provide the first description of the molecular response of the hypothalamic-pituitary-gonadal (HPG) axis of male big brown bats (Eptesicus fuscus) in response to short-term stress using a standardized restraint manipulation. This acute stressor was sufficient to upregulate plasma corticosterone and resulted in a rapid decrease in circulating testosterone. While we did not find differences in the mRNA expression of key steroidogenic enzymes (StAR, aromatase, 5-alpha reductase), seminiferous tubule diameter was reduced in stressed bats coupled with a 5-fold increase in glucocorticoid receptor (GR) mRNA expression in the testes. These changes, in part, may be mediated by RFamide-related peptide (RFRP) because fewer immunoreactive cell bodies were detected in the brains of stressed bats compared with controls - suggesting a possible increase in secretion - and increased RFRP expression locally in the gonads. The rapid sensitivity of the bat testes to stress may be connected to deleterious impacts on tissue health and function as supported by significant transcriptional upregulation of key pro-apoptotic signaling molecules (Bax, cytochrome c). Experiments like this broadly contribute to our understanding of the stronger ecological predictions regarding physiological responses of bats within the context of stress, which may impact decisions surrounding animal handling and conservation approaches.

Glucocorticoid receptor expression in blood, but not across brain regions, reveals long-term effects of early life adversity in zebra finches

Early-life environment can affect organisms for life on many levels. The glucocorticoid receptor (GR) gene has a pivotal role mediating organismal physiological and behavioral responses to environmental change, and is sensitive to early-life environmental conditions and epigenetic programming. Longitudinal studies require non-lethal sampling of peripheral tissues (e.g. blood), but this approach is dependent on the extent to which GR expression in peripheral tissues covaries with GR expression in central tissues. To test for the long-term effects of early life adversity on GR expression across brain and peripheral tissues, we manipulated developmental conditions of captive zebra finches (n = 45), rearing them in either benign or harsh conditions through manipulation of parental foraging costs. We measured relative GR mRNA expression in blood and five brain regions in adulthood: hippocampus, hypothalamus, amygdala, ventral striatum, and the nidopallium caudolaterale (analogous to the mammalian prefrontal cortex), using qPCR. We further tested whether GR expression was modulated by natal brood size (which affected growth), age at sampling, and sex. GR expression correlations among tissues varied widely in magnitude and direction, ranging from -0.27 to +0.80, indicating that our understanding of developmental effects on GR expression and associated phenotypes needs to be region specific rather than organism wide. A more consistent pattern was that GR expression increased with age in blood, ventral striatum and hippocampus; GR expression was independent of age in other tissues. Developmental treatment did not affect GR expression in any of the tissues measured directly, but in blood and ventral striatum of adult females we found a positive correlation between nestling mass and GR expression. Thus, GR expression in blood was affected by early life conditions as reflected in growth in adult females, a pattern also found in one brain tissue, but not ubiquitous across brain regions. These results point at sex-dependent physiological constraints during development, shaping early life effects on GR expression in females only. Further study is required to investigate whether these tissue-dependent effects more generally reflect tissue-dependent long-term effects of early life adversity. This, together with investigating the physiological consequences of GR expression levels on individual performance and coping abilities, will be fundamental towards understanding the mechanisms mediating long-term impacts of early life, and the extent to which these can be quantified through non-lethal sampling.

Epigenetic mechanisms underlying stress-induced visceral pain: Resilience versus vulnerability in a two-hit model of early life stress and chronic adult stress.

Women with a history of early life stress (ELS) have a higher risk of developing irritable bowel syndrome (IBS). In addition, chronic stress in adulthood can exacerbate IBS symptoms such as abdominal pain due to visceral hypersensitivity. We previously showed that sex and the predictability of ELS determine whether rats develop visceral hypersensitivity in adulthood. In female rats, unpredictable ELS confers vulnerability and results in visceral hypersensitivity, whereas predictable ELS induces resilience and does not induce visceral hypersensitivity in adulthood. However, this resilience is lost after exposure to chronic stress in adulthood leading to an exacerbation of visceral hypersensitivity. Evidence suggests that changes in histone acetylation at the promoter regions of glucocorticoid receptor (GR) and corticotrophin-releasing factor (CRF) in the central nucleus of the amygdala (CeA) underlie stress-induced visceral hypersensitivity. Here, we aimed to investigate the role of histone acetylation in the CeA on visceral hypersensitivity in a two-hit model of ELS followed by chronic stress in adulthood. Male and female neonatal rats were exposed to unpredictable, predictable ELS, or odor only (no stress control) from postnatal days 8 to 12. In adulthood, rats underwent stereotaxic implantation of indwelling cannulas. Rats were exposed to chronic water avoidance stress (WAS, 1 h/day for 7 days) or SHAM stress and received infusions of vehicle, the histone deacetylase inhibitor trichostatin A (TSA) or the histone acetyltransferase inhibitor garcinol (GAR) after each WAS session. 24 h after the final infusion, visceral sensitivity was assessed and the CeA was removed for molecular experiments. In the two-hit model (ELS + WAS), female rats previously exposed to predictable ELS, showed a significant reduction in histone 3 lysine 9 (H3K9) acetylation at the GR promoter and a significant increase in H3K9 acetylation at the CRF promoter. These epigenetic changes were associated with changes in GR and CRF mRNA expression in the CeA and an exacerbation of stress-induced visceral hypersensitivity in female animals. TSA infusions in the CeA attenuated the exacerbated stress-induced visceral hypersensitivity, whereas GAR infusions only partially ameliorated ELS+WAS induced visceral hypersensitivity. The two-hit model of ELS followed by WAS in adulthood revealed that epigenetic dysregulation occurs after exposure to stress in two important periods of life and contributes to the development of visceral hypersensitivity. These aberrant underlying epigenetic changes may explain the exacerbation of stress-induced abdominal pain in IBS patients.

Placental leukocyte infiltration accompanies gestational changes induced by hyperthyroidism.

The endocrine and immunological disruption induced by hyperthyroidism could alter gestation, placenta, and fetal development. This study suggests an immunological role of thyroid hormones in gestation. Thyroid dysfunctions lead to metabolic, angiogenic, and developmental alterations at the maternal-fetal interface that cause reproductive complications. Thyroid hormones (THs) act through their nuclear receptors that interact with other steroid hormone receptors. Currently, immunological regulation by thyroid status has been characterized to a far less extent. It is well known that THs exert regulatory function on immune cells and modulate cytokine expression, but how hyperthyroidism (hyper) modulates placental immunological aspects leading to placental alterations is unknown. This work aims to throw light on how hyper modulates immunological and morphological placental aspects. Control and hyper (induced by a daily s.c. injection of T4 0.25 mg/kg) Wistar rats were mated 8 days after starting T4 treatment and euthanized on days 19 (G19) and 20 (G20) of pregnancy. We removed the placenta to perform qPCR, flow cytometry, immunohistochemistry, Western blot and histological analysis, and amniotic fluid and serum to evaluate hormone levels. We observed that hyper increases the fetal number, fetal weight, and placental weight on G19. Moreover, hyper induced an endocrine imbalance with higher serum corticosterone and changed placental morphology, specifically the basal zone and decidua. These changes were accompanied by an increased mRNA expression of glucocorticoid receptor and monocyte chemoattractant protein-1, an increased mRNA and protein expression of prolactin receptor, and an increase in CD45+ infiltration. Finally, by in vitro assays, we evidenced that TH induced immune cell activation. In summary, we demonstrated that hyper modulates immunological and morphological placental aspects and induces fetal phenotypic changes, which could be related to preterm labor observed in hyper.

Effect of maternal periconceptional undernutrition in sheep on cortisol regulation in offspring from mid-late gestation, through to adulthood.

Maternal periconceptional undernutrition (PCUN) alters fetal hypothalamic-pituitary-adrenal axis (HPAA) function and placental glucocorticoid metabolism in sheep. The effects of PCUN on HPAA function in adult life are not known. We investigated the effects of PCUN on fetal adrenal development across gestation and on cortisol regulation in adult offspring. Ewes were undernourished from 61 days before to 30 days after conception ('PCUN') or fed ad libitum ('N'). mRNA expression in the fetal adrenal gland of ACTH receptor (ACTHR), steroidogenic acute regulatory protein (STAR), cytochrome P450 17A1 (CYP17A1), 11beta-hydroxysteroid-dehydrogenase type 2 (11βHSD2), insulin-like growth factor-2 (IGF2), and in the fetal hippocampus of 11βHSD1, 11βHSD2, mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) was determined at 50 (adrenal only), 85, 120 and 131 days of gestation (term=148 days). In adult offspring (≥ 3 years, N; 10 female, 5 male, PCUN; 10 female, 10 male) a combined arginine vasopressin (AVP, 0.1 μg/kg) and corticotropin-releasing hormone (CRH, 0.5 μg/kg) challenge and a metyrapone (40 mg/kg) challenge were undertaken. mRNA expression of ACTHR, STAR and CYP17A1 were determined in adult adrenals. Fetal adrenal STAR, CYP17A1 and IGF2 mRNA expression were not different between groups in early gestation but were higher in PCUN than N at 131 days' gestation (all p<0.01). PCUN reduced fetal hippocampal MR and GR mRNA expression by 50% at 85 day, but not in later gestation. Adult offspring plasma cortisol responses to AVP+CRH or metyrapone were not different between groups. Plasma ACTH response to AVP+CRH was lower in PCUN males but ACTH response to metyrapone was not different between groups. Adult adrenal ACTHR, STAR, and CYP17A1 mRNA expression were not affected by PCUN. We conclude that the effects of PCUN on fetal HPAA function that became apparent in late gestation, are not reflected in adrenal cortisol secretion in mid-adulthood.

Psilocybin rescues depressive phenotype and modulates serotonin-2A and glucocorticoid receptor mRNA expression in brain cortex of a stress animal model

Psilocybin rescues depressive phenotype and modulates serotonin-2A and glucocorticoid receptor mRNA expression in brain cortex of a stress animal model

염분 변화에 따른 명태(Gadus Chalcogrammus)의 스트레스 반응; 혈액생리학적 변화 및 유전자 발현

The study evaluated the change of stress indicators in plasma and mRNA expression levels of stress-related genes in head-kidney and liver of walleye pollock, Gadus chalcogrammus according to acute salinity fluctuation. Walleye pollocks were exposed for 24 hours in five groups, as salinity are 34, 30, 25, 20, and 15 psu. The levels of hematocrit (Ht), glutamic oxaloacetate transaminase (GOT), cortisol, glucose, and superoxide dismutase (SOD) in plasma were increased as the salinity of the breeding water decreased. Ht increased with 37.5 ± 1% at 20 psu. GOT with 41.0 ± 5.03 U/L, cortisol with 882.73 ± 32.73 ng/mL, and glucose with 67.67±11.6 ng/dL increased a significant difference at 25 psu. The SOD activity levels in plasma were highest at 15 psu with 3.51 ± 0.13 U/mL. Plasma hemoglobin (Hb) and glutamic pyruvic transaminase (GPT) did not show a statistically significant difference according to salinity, but showed a tendency to increase as the salinity decreased. Total protein (TP) levels in plasma were the highest with 5.9 ± 0.61 g/dL at 25 psu. The relative mRNA expression of stress-related genes was investigated in the head-kidney and liver of walleye pollocks, and the mRNA expression of steroidogenic acute regulatory protein (StAR) and heat shock protein 70 (HSP70) increased, as the salinity decreased from 25 psu, whereas glucocorticoid receptor (GR) mRNA expression decreased as the salinity decreased. These results suggest that walleye pollocks become stressed-condition to salinity below 25 psu, but homeostasis can be maintained up to 15 psu in short-term.

Xiangshao Granules reduce the aggressive behavior and hippocampal injury of premenstrual irritability in rats by regulating JIK/JNK/p38 signal pathway

Ethnopharmacological relevanceAs a typical prescription for soothing the liver, Xiangshao granule has a good effect on the symptoms of irritability and anxiety. Clinical evidence suggests that it has significant efficacy in the treatment of Premenstrual dysphoria disorder (PMDD). However, the underlying mechanism remains unclear. Aim of the studyPMDD is a common disease in women of childbearing age, seriously affecting their family, society, and daily work life. The registered herbal medicine, Xiangshao granules, is used for relieving PMDD dysphoria and irritability symptoms with excellent efficacy in China. This study was focused on the deep intervention mechanism of Xiangshao granules in treating PMDD. Materials and methodsThe vaginal smear and open field test were used to screen rats in nonreception phase of estrus cycle with similar macroscopic behaviors and regular estrus cycle. The rat model of PMDD irritability was established through social isolation and residential invasion, with which, the irritability symptoms of PMDD patients with menstrual cycle dependence was also well simulated. Elevated plus Maze Test and Social interaction activities were used to measure the anxiety-like behavior of rats. TUNEL Staining and Hematoxylin-Eosin staining were used to measure apoptosis of hippocampal neurons. RT-PCR, Western blot and immunofluorescence were used to measure the expression of GR, JIK, p-JIK, p38, P–P38, JNK, caspase 3, and caspase 12. ResultsIn this study, Xiangshao granules showed consistent therapeutic effects similar with those in clinic, significantly reducing aggressive and anxiety-like behaviors with improved social skills in PMDD rats. In mechanism, Xiangshao granules lowered the apoptosis of hippocampal neurons and weakened the morphological damage of the hippocampal brain evidenced by the decreased mRNA and protein expression of glucocorticoid receptor, caspase-3, and caspase-12. In addition, administration of Xiangshao granules led to the decreased expression of JIK in the PMDD irritability rat model which agreed well with the previous studies. The JNK/p38 mitogen-activated protein kinases (MAPKs) signaling pathway is abnormally activated in the hippocampal brain region of PMDD rats, while treated with Xiangshao granules could increase JIK expression and inhibit the abnormal activation of the JNK/p38 MAPK signaling pathway, effectively reducing the stress damage in the hippocampus. ConclusionsXiangshao Granules Reduce the Aggressive Behavior and Hippocampal Injury of Premenstrual Irritability in Rats by Regulating JIK/JNK/p38 Signal Pathway.

Simultaneous activation of genes encoding urea cycle enzymes and gluconeogenetic enzymes coincides with a corticosterone surge period before metamorphosis in Xenopus laevis.

Amphibian tadpoles are postulated to excrete ammonia as nitrogen metabolites but to shift from ammonotelism to ureotelism during metamorphosis. However, it is unknown whether ureagenesis occurs or plays a functional role before metamorphosis. Here, the mRNA-expression levels of two urea cycle enzymes (carbamoyl phosphate synthetase I [CPSI] and ornithine transcarbamylase [OTC]) were measured beginning with stage-47 Xenopus tadpoles at 5 days post-fertilization (dpf), between the onset of feeding (stage 45, 4 dpf) and metamorphosis (stage 55, 32 dpf). CPSI and OTC expression levels increased significantly from stage 49 (12 dpf). Urea excretion was also detected at stage 47. A transient corticosterone surge peaking at stage 48 was previously reported, supporting the hypothesis that corticosterone can induce CPSI expression in tadpoles, as found in adult frogs and mammals. Stage-46 tadpoles were exposed to a synthetic glucocorticoid, dexamethasone (Dex, 10-500 nM) for 3 days. CPSI mRNA expression was significantly higher in tadpoles exposed to Dex than in tadpoles exposed to the vehicle control. Furthermore, glucocorticoid receptor mRNA expression increased during the pre-metamorphic period. In addition to CPSI and OTC mRNA upregulation, the expression levels of three gluconeogenic enzyme genes (glucose 6-phosphatase, phosphoenolpyruvate carboxykinase, and fructose-1,6-bisphosphatase 1) increased with the onset of urea synthesis and excretion. These results suggest that simultaneous induction of the urea cycle and gluconeogenic enzymes coincided with a corticosterone surge occurring prior to metamorphosis. These metabolic changes preceding metamorphosis may be closely related to the onset of feeding and nutrient accumulation required for metamorphosis.

Juvenile social isolation affects the structure of the tanycyte–vascular interface in the hypophyseal portal system of the adult mice

Accumulating evidence indicates that social stress in the juvenile period affects hypothalamic–pituitary–adrenal (HPA) axis activity in adulthood. The biological mechanisms underlying this phenomenon remain unclear. We aimed to elucidate them by comparing adult mice that had experienced social isolation from postnatal day 21–35 (juvenile social isolation (JSI) group) with those reared normally (control group). JSI group mice showed an attenuated HPA response to acute swim stress, while the control group had a normal response to this stress. Activity levels of the paraventricular nucleus in both groups were comparable, as shown by c-Fos immunoreactivities and mRNA expression of c-Fos, Corticotropin-releasing factor (CRF), Glucocorticoid receptor, and Mineralocorticoid receptor. We found greater vascular coverage by tanycytic endfeet in the median eminence of the JSI group mice than in that of the control group mice under basal condition and after acute swim stress. Moreover, CRF content after acute swim stress was greater in the median eminence of the JSI group mice than in that of the control group mice. The attenuated HPA response to acute swim stress was specific to JSI group mice, but not to control group mice. Although a direct link awaits further experiments, tanycyte morphological changes in the median eminence could be related to the HPA response.

Expression patterns of AMPK and genes associated with lipid metabolism in newly hatched chicks during the metabolic perturbation of fasting and refeeding

Fasting-refeeding perturbation has been extensively used to reveal specific genes and metabolic pathways that control energy metabolism in chickens. In this study, 200 chickens were randomly assigned to 2 groups after hatching: the control group (C, fed ad libitum) and the fasting-refeeding group (T, water ad libitum). The chicks in Group T were fasted for 72 h, and then fed for another 48 h. Liver, hypothalamus, and adipose samples were collected at 0 (F0), 24 (F24), 48 (F48), and 72 h (F72) after fasting and 4 (FR4), 12 (FR12), 24 (FR24), and 48 h (FR48) after refeeding, respectively. Results showed that Group T had a significantly higher number of liver vacuoles (P < 0.05 or P < 0.01) and a significantly lower gray value of Sudan IIIstained sections (P < 0.05 or P < 0.01) than Group C at F48-FR48. In addition, compared with the Group C, fasting and refeeding reduced the expression of stearoyl CoA desaturase (SCD) mRNA (P < 0.05 or P < 0.01) in the liver and adipose tissues, the expression of glucocorticoid receptor (GR) mRNA (P < 0.05 or P < 0.01) in the liver, adipose, and hypothalamus tissues, and the expression of fatty acid synthase (FAS) mRNA (P < 0.05 or P < 0.01) in the liver at F24-FR24. Moreover, relative to those in Group C, fasting and refeeding increased the mRNA expression levels of adenosine monophosphate-activated protein kinase (AMPK) α, AMPKβ, and AMPKγ in the hypothalamus (P < 0.05 or P < 0.01) at F24-FR24. In conclusion, fasting and refeeding increased the fat content of the liver, and the expression of lipolytic genes in the hypothalamus (e.g., AMPKα, AMPKβ, and AMPKγ) but decreased the expression of fat synthesis genes in the liver (e.g., SCD, GR, and FAS), adipose (SCD and GR), and hypothalamus (GR).

Trauma-induced human glucocorticoid receptor expression increases predict subsequent HPA-axis blunting in a prospective longitudinal design

One of the hallmarks of post-traumatic stress disorder (PTSD) is abnormalities in the HPA-axis. This includes alterations in its negative feedback regulation. Although altered glucocorticoid receptor (GR) mRNA expression is thought to play a crucial role herein, direct longitudinal evidence in humans is lacking to support this assumption. The current prospective longitudinal study assessed the consequence of repeated trauma exposure on GR mRNA expression from saliva samples in early-career police recruits (n = 112) by assessing them before and after trauma exposure. We did not observe a relationship between change in GR mRNA expression and development of PTSD symptom severity. However, the more traumatic events were experienced during police training the stronger GR mRNA expression was increased. Moreover, increases in GR mRNA expression were associated with blunted HPA-axis stress-reactivity at follow-up compared to baseline. This study provides the first longitudinal evidence of a dose-response relationship between trauma and human GR mRNA expression (extracted from saliva) changes; therefore, replication is warranted. Our finding might contribute a possible explanatory framework for blunted HPA-axis function associated with PTSD.

[Effect of wheat-grain moxibustion on the expression of 5-HT and cortisol in the serum, and MR and GR in the hippocampus in rats with hypothyroidism complicated with depression].

To observe the effect of wheat-grain moxibustion on behavior, 5-hydroxytryptamine (5-HT) and cortisol in the serum, mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hippocampus in rats with hypothyroidism complicated with depression, and to explore the possible mechanism of wheat-grain moxibustion on improving depression in rats with hypothyroidism. A total of 32 SPF SD rats were randomly divided into a blank group, a model group, a medication group and a wheat-grain moxibustion group, 8 rats in each group. Except for the blank group, the rats in the remaining groups were treated with intragastric administration of 0.1% propylthiouracil (PTU) suspension at 1 mL/100 g, once a day for 4 weeks to establish the rat model of hypothyroidism, and whether the rats were accompanied with depression-like behavior determined through behavioristics evaluation. The rats in the medication group were intervened with euthyrox at 0.9 mL/100 g, once a day, for 4 weeks; the rats in the wheat-grain moxibustion group were treated with wheat-grain moxibustion at "Dazhui" (GV 14), "Mingmen" (GV 4), "Shenshu" (BL 23) and "Pishu" (BL 20), 7 cones each acupoint, once a day, six times a week for 4 weeks. After the intervention, the depression status was observed by behavioristics test; the contents of thyroid stimulating hormone (TSH), total thyroxine (TT4), 5-HT and cortisol in the serum were detected by ELISA; the protein expressions of MR and GR in hippocampus were detected by Western blot; the expressions of MR mRNA and GR mRNA in the hippocampus were detected by real-time PCR. Before the intervention, compared with the blank group, the scores of open field test (OFT) were decreased and the immobility time of tail suspension test (TST) was prolonged (P<0.05); the serum TSH contents were increased and TT4 contents were decreased (P<0.01) in the other three groups. After the intervention, compared with the model group, the vertical score of OFT was increased and the immobility time of forced swimming test (FST) was prolonged in the medication group (P<0.05), while the scores of three items of OFT were increased (P<0.05, P<0.01), and the immobility time of FST and TST was shortened in the wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the medication group, the immobility time of TST and FST in the wheat-grain moxibustion group was shorter (P<0.05, P<0.01). Compared with the blank group, in the model group, the contents of serum TSH and cortisol were increased (P<0.01, P<0.001), while the contents of serum TT4 and 5-HT were decreased (P<0.01, P<0.001). Compared with the model group, the contents of serum TT4 and 5-HT were increased, while the contents of serum TSH and cortisol were decreased in the medication group and wheat-grain moxibustion group (P<0.01, P<0.05). Compared with the blank group, the protein and mRNA expression of MR, GR in the hippocampus in the model group was decreased (P<0.01, P<0.05, P<0.001); compared with the model group, the protein and mRNA expression of MR in the hippocampus in the medication group were increased (P<0.05), and the protein expression of MR, GR and mRNA expression of MR in the hippocampus in the wheat-grain moxibustion group were increased (P<0.05, P<0.01). Compared with the medication group, the expression of MR mRNA in the wheat-grain moxibustion group was increased (P<0.05). Wheat-grain moxibustion could significantly improve thyroid function and depression in rats with hypothyroidism. Its mechanism may be related to up-regulating the protein and mRNA expression of MR and GR in the hippocampus, and then affecting the expression of serum cortisol and 5-HT.

Effects of acute low temperature stress on the hormones and gene expression of glucocorticoid receptor of large yellow croaker Larimichthys crocea.

The neuroendocrine system of fish responds to low temperature via regulating hormones. To explore the adaptability of Larimichthys crocea to low temperature, the levels of the plasma cortisol, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), total cholesterol (TC), and glucose were determined after exposure to low temperature and during subsequent rewarming. Furthermore, the mRNA expression of the glucocorticoid receptor (GR) gene was analyzed under the stress. We found that the levels of the plasma cortisol, TSH, T3, glucose, and TC increased under the low temperature stress, suggesting that elevated hormones may be conducive to promoting the mobilization of the glucose and lipid in L. crocea exposed to low temperature. During the rewarming period, the plasma cortisol level decreased, whereas the T3 level was still significantly higher than that in the control group. Notably, the plasma T4 level was unaffected by the temperature changes. Furthermore, the sequence alignment and phylogenetic tree analysis revealed that the GR protein of L. crocea had high homology and a similar protein structure with those from other teleosts. Under the low temperature stress, the GR mRNA expression increased in the brain and head kidney, whereas it basically returned to the control level following rewarming. These findings revealed the changes of the hormones and the potential function of the GR gene in L. crocea following exposure to low temperature, providing some insights into breeding low temperature-resistant varieties of L. crocea.

Hypothalamic-pituitary-adrenal axis regulation and organization in urban and rural song sparrows

Urban habitats present animals with persistent disturbances and acute stressors not present in rural habitats or present at significantly lower levels. Differences in the glucocorticoid stress response could underlie colonization of these novel habitats. Despite urban habitats characterization as more stressful, previous comparisons of urban and rural birds have failed to find consistent differences in baseline and stress induced glucocorticoid levels. Another aspect of glucocorticoid regulation that could underlie an animal’s ability to inhabit novel habitats, but has yet to be well examined, is more efficient termination of the glucocorticoid stress response which would allow birds in urban habitats to recover more quickly after a disturbance. The glucocorticoid stress response is terminated by negative feedback achieved primarily through their binding of receptors in the hippocampus and hypothalamus and subsequent decreased synthesis and release from the adrenals. We investigated if male song sparrows (Melospiza melodia) in urban habitats show more efficient termination of the glucocorticoid stress response than their rural counterparts using two approaches. First, we measured glucocorticoid receptor, mineralocorticoid receptor and 11β-HSD2 (an enzyme that inactivates corticosterone) mRNA expression in negative feedback targets of the brain (the hippocampus and hypothalamus) as a proxy measure of sensitivity to negative feedback. Second, we measured plasma corticosterone levels after standardized restraint and again following a challenge with the synthetic glucocorticoid, dexamethasone, as a means of assessing how quickly birds decreased glucocorticoid synthesis and release. Though there were no differences in the hypothalamus of urban and rural song sparrows, urban birds had lower glucocorticoid receptor and 11β-HSD2 mRNA expression in the hippocampus. Further, urban and rural birds had similar reductions in corticosterone following the dexamethasone challenge, suggesting that they do not differ in how quickly they decrease glucocorticoid synthesis and release. Thus, urban and rural song sparrows display similar termination of the glucocorticoid stress response even though urban birds have decreased hippocampal glucocorticoid receptor and 11β-HSD2 abundance.

A preferential switch between placental GR exon 1 promoter variants in the presence of maternal asthma or inflammation upregulates GRα D isoforms

IntroductionThe human placenta expresses multiple glucocorticoid receptor (GR) isoforms that may be partially regulated by the untranslated 5’ exon 1 GR gene promoter region which consists of 9 different promoters and 13 splice variants. The objective of this study was to determine which GR exon 1 variants are expressed in the human placenta and relate these findings to GR mRNA and protein expression. MethodsPlacental extracts from pregnancies with or without the complication of maternal asthma and trophoblast cells exposed to an inflammatory challenge in vitro were examined using PCR and Western blot to measure GR exon 1 variants, GR splice variant mRNA and GR protein isoforms, respectively. ResultsAll 9 GR exon 1 variants were detectable in the human placenta and included GR exons 1A, 1B, 1C, 1D, 1E, 1F, 1H, 1I and 1J. In the presence of maternal asthma and a male fetus there was preferential expression of GR exon 1B, 1C, IF and 1J (KW-ANOVA, P < 0.05) which were positively correlated with GRα D3 protein isoform. In female placentae from pregnancies complicated by asthma there was no upregulation of any exon 1 variant (KW-ANOVA, P < 0.05). Exposure of BeWo trophoblast cell line to an inflammatory challenge, lipopolysaccharide, in vitro, resulted in preferential expression of GR exon 1B, 1D, 1E and 1H and associated with GRα-D1 protein upregulation. DiscussionThe preferential expression of different GR exon 1 promoters drive the upregulation of GRα D isoforms and contribute to glucocorticoid resistance observed in male placentae of pregnancies complicated by asthma.

Male Goal-Tracker and Sign-Tracker Rats Do Not Differ in Neuroendocrine or Behavioral Measures of Stress Reactivity.

Environmental cues attain the ability to guide behavior via learned associations. As predictors, cues can elicit adaptive behavior and lead to valuable resources (e.g., food). For some individuals, however, cues are transformed into incentive stimuli and elicit motivational states that can be maladaptive. The goal-tracker (GT)/sign-tracker (ST) animal model captures individual differences in cue-motivated behaviors, with reward-associated cues serving as predictors of reward for both phenotypes but becoming incentive stimuli to a greater degree for STs. While these distinct phenotypes are characterized based on Pavlovian conditioned approach (PavCA) behavior, they exhibit differences on a number of behaviors relevant to psychopathology. To further characterize the neurobehavioral endophenotype associated with individual differences in cue-reward learning, neuroendocrine and behavioral profiles associated with stress and anxiety were investigated in male GT, ST, and intermediate responder (IR) rats. It was revealed that baseline corticosterone (CORT) increases with Pavlovian learning, but to the same degree, regardless of phenotype. No significant differences in behavior were observed between GTs and STs during an elevated plus maze (EPM) or open field test (OFT), nor were there differences in CORT response to the OFT or physiological restraint. Upon examination of central markers associated with stress reactivity, we found that STs have greater glucocorticoid receptor (GR) mRNA expression in the ventral hippocampus, with no phenotypic differences in the dorsal hippocampus or prelimbic cortex (PrL). These findings demonstrate that GTs and STs do not differ on stress-related and anxiety-related behaviors, and suggest that differences in neuroendocrine measures between these phenotypes can be attributed to distinct cue-reward learning styles.

The Influence of Glucocorticoid Receptor on Sex Differences of Gene Expression Profile in Skeletal Muscle

ABSTRACT Skeletal muscle functions as a locomotory system and maintains whole-body metabolism. Sex differences in such skeletal muscle morphology and function have been documented; however, their underlying mechanisms remain elusive. Glucocorticoids are adrenocortical hormones maintaining homeostasis, including regulating whole-body energy metabolism in addition to stress response. In skeletal muscle, glucocorticoids can reduce the synthesis of muscle proteins and simultaneously accelerate the breakdown of proteins to regulate skeletal muscle mass and energy metabolism via a transcription factor glucocorticoid receptor (GR). We herein evaluated the related contributions of the GR to sex differences of gene expression profiles in skeletal muscle using GR-floxed (GRf/f) and skeletal muscle-specific GR knockout (GRmKO) mice. There were no differences in GR mRNA and protein expression levels in gastrocnemius muscle between males and females. A DNA microarray analysis using gastrocnemius muscle from GRf/f and GRmKO mice revealed that, although most gene expression levels were identical in both sexes, genes related to cholesterol and apolipoprotein synthesis and fatty acid biosynthesis and the immunological system were predominantly expressed in males and females, respectively, in GRf/f but not in GRmKO mice. Moreover, many genes were up-regulated in response to starvation in GRf/f but not in GRmKO mice, many of which were sex-independent and functioned to maintain homeostasis, while genes that showed sex dominance related to a variety of functions. Although the genes expressed in skeletal muscle may be predominantly sex-independent, sex-dominant genes may relate to sex differences in energy metabolism and the immune system and could be controlled by the GR.