Mechanisms for the species difference between mouse and pig oocytes in their sensitivity to glucorticoids.

Although in vitro exposure to physiological concentrations of glucorticoids did not affect maturation of mouse oocytes, it significantly inhibited nuclear maturation of pig oocytes. Studies on this species difference in oocyte sensitivity to glucocorticoids will contribute to our understanding of how stress/glucocorticoids affect oocytes. We showed that glucorticoid receptors (NR3C1) were expressed in both oocytes and cumulus cells (CCs) of both pigs and mice; however, while cortisol inhibition of oocyte maturation was overcome by NR3C1 inhibitor RU486 in pigs, it could not be relieved by RU486 in mice. The mRNA level of 11ß-hydroxysteroid dehydrogenase 1 (HSD11B1) was significantly higher than that of HSD11B2 in pig cumulus-oocyte complexes (COCs), whereas HSD11B2 was exclusively expressed in mouse COCs. Pig and mouse cumulus-denuded oocytes (DOs) expressed HSD11B2 predominantly and exclusively, respectively. In the presence of cortisol, although inhibiting HSD11B2 decreased maturation rates of COCs in both species, inhibiting HSD11B1 improved maturation of pig COCs while having no effect on mouse COCs. Cortisol-cortisone interconversion observation confirmed high HSD11B1 activities in pig oocytes but none in mouse oocytes, a higher HSD11B2 activity in mouse than in pig oocytes, and a rapid cortisol-cortisone interconversion in pig COCs catalyzed by HSD11B1 from CCs and HSD11B2 from DOs. In conclusion, the species difference in glucocorticoid sensitivity between pig and mouse oocytes is caused by their different contents/ratios of HSD11B1 and HSD11B2, which maintain different concentrations of active glucocorticoids. While cortisol inhibited pig oocytes by interacting with NR3C1, glucocorticoid suppression of mouse oocytes was apparently not mediated by NR3C1.

Rac1 GTPase regulates 11ß hydroxysteroid dehydrogenase type 2 and fibrotic remodeling.

The aim of the study was to characterize the role of Rac1 GTPase for the mineralocorticoid receptor (MR)-mediated pro-fibrotic remodeling. Transgenic mice with cardiac overexpression of constitutively active Rac1 (RacET) develop an age-dependent phenotype with atrial dilatation, fibrosis, and atrial fibrillation. Expression of MR was similar in RacET and WT mice. The expression of 11ß hydroxysteroid dehydrogenase type 2 (11ß-HSD2) was age-dependently up-regulated in the atria and the left ventricles of RacET mice on mRNA and protein levels. Statin treatment inhibiting Rac1 geranylgeranylation reduced 11ß-HSD2 up-regulation. Samples of human left atrial myocardium showed a positive correlation between Rac1 activity and 11ß-HSD2 expression (r = 0.7169). Immunoprecipitation showed enhanced Rac1-bound 11ß-HSD2 relative to Rac1 expression in RacET mice that was diminished with statin treatment. Both basal and phorbol 12-myristate 13-acetate (PMA)-induced NADPH oxidase activity were increased in RacET and correlated positively with 11ß-HSD2 expression (r = 0.788 and r = 0.843, respectively). In cultured H9c2 cardiomyocytes, Rac1 activation with l-buthionine sulfoximine increased; Rac1 inhibition with NSC23766 decreased 11ß-HSD2 mRNA and protein expression. Connective tissue growth factor (CTGF) up-regulation induced by aldosterone was prevented with NSC23766. Cardiomyocyte transfection with 11ß-HSD2 siRNA abolished the aldosterone-induced CTGF up-regulation. Aldosterone-stimulated MR nuclear translocation was blocked by the 11ß-HSD2 inhibitor carbenoxolone. In cardiac fibroblasts, nuclear MR translocation induced by aldosterone was inhibited with NSC23766 and spironolactone. NSC23766 prevented the aldosterone-induced proliferation and migration of cardiac fibroblasts and the up-regulation of CTGF and fibronectin. In conclusion, Rac1 GTPase regulates 11ß-HSD2 expression, MR activation, and MR-mediated pro-fibrotic signaling.

A repressive role of enhancer of zeste homolog 2 in 11ß-hydroxysteroid dehydrogenase type 2 expression in the human placenta.

The expression of 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), which acts as a placental glucocorticoid barrier, is silenced in cytotrophoblasts but substantially up-regulated during syncytialization. However, the repressive mechanism of 11ß-HSD2 expression before syncytialization and how this repression is lifted during syncytialization remain mostly unresolved. Here we found that enhancer of zeste homolog 2 (EZH2) accounts for the silence of 11ß-HSD2 expression via trimethylation of histone H3 lysine 27 at the promoter of the 11ß-HSD2 gene. Further studies revealed that, upon syncytialization, human chorionic gonadotropin reduced the phosphorylation of retinoblastoma protein (pRB) via activation of the cAMP/PKA pathway, which sequesters E2F transcription factor 1 (E2F1), the transcription factor for EZH2 expression. As a result of inactivation of the pRB-E2F1-EZH2 pathway, the repressive marker trimethylation of histone H3 lysine 27 at the 11ß-HSD2 promoter is removed, which leads to the robust expression of 11ß-HSD2 during syncytialization.

Myeloid cells are capable of synthesizing aldosterone to exacerbate damage in muscular dystrophy.

FDA-approved mineralocorticoid receptor (MR) antagonists are used to treat heart failure. We have recently demonstrated efficacy of MR antagonists for skeletal muscles in addition to heart in Duchenne muscular dystrophy mouse models and that mineralocorticoid receptors are present and functional in skeletal muscles. The goal of this study was to elucidate the underlying mechanisms of MR antagonist efficacy on dystrophic skeletal muscles. We demonstrate for the first time that infiltrating myeloid cells clustered in damaged areas of dystrophic skeletal muscles have the capacity to produce the natural ligand of MR, aldosterone, which in excess is known to exacerbate tissue damage. Aldosterone synthase protein levels are increased in leukocytes isolated from dystrophic muscles compared with controls and local aldosterone levels in dystrophic skeletal muscles are increased, despite normal circulating levels. All genes encoding enzymes in the pathway for aldosterone synthesis are expressed in muscle-derived leukocytes. 11ß-HSD2, the enzyme that inactivates glucocorticoids to increase MR selectivity for aldosterone, is also increased in dystrophic muscle tissues. These results, together with the demonstrated preclinical efficacy of antagonists, suggest MR activation is in excess of physiological need and likely contributes to the pathology of muscular dystrophy. This study provides new mechanistic insight into the known contribution of myeloid cells to muscular dystrophy pathology. This first report of myeloid cells having the capacity to produce aldosterone may have implications for a wide variety of acute injuries and chronic diseases with inflammation where MR antagonists may be therapeutic.

Regulation of glucocorticoid-related genes and receptors/regulatory enzyme expression in intrauterine growth restriction filial rats.

AIMS: This study aims to explore factors that influence glucocorticoid (GC)-related genes and receptors/regulatory enzyme expression in intrauterine growth restriction (IUGR) filial rats. MAIN METHODS: An IUGR animal model was established by starvation, and brain tissue was removed after birth. Affymetrix Rat Gene 2.0 ST microarray was used to screen different expressions of GC-related genes in IUGR brain tissues. The mRNA and protein levels of related genes were validated by RT-PCR and western blot. KEY FINDINGS: Results of the microarray revealed that the expression of 11ß-Hsd2 was significantly downregulated in the IUGR group compared to the control group. Although Nr3c1 exhibited an overexpression trend in the IUGR group, there were no significant differences between the two groups. Further analysis suggests that the 11ß-Hsd2 was negatively correlated to Nr3c1. In the transcription level, the expression level of 11ß-Hsd2 mRNA decreased in the IUGR group, while the mRNA expression level of Nr3c1 significantly increased. In the protein level, the expression of 11ß-Hsd2 significantly decreased in the IUGR group; while the expression of Nr3c1 significantly increased in the IUGR group. However, there were no significant differences in Nr3c1 phosphorylated at S211 and S266 between the IUGR and control groups. SIGNIFICANCE: The expression of Nr3c1 was mainly regulated by 11ß-Hsd2, which could significantly inhibit its expression in IUGR rats. Phosphorylation on site S211 was the major activated form of Nr3c1. We speculate that IUGR brain damage was caused by excessive amounts of GC due to significant activation by Nr3c1.

Citosine-Adenine-Repeat Microsatellite of 11ß-hydroxysteroid dehydrogenase 2 Gene in Hypertensive Children.

BACKGROUND: The impairment of 11ß-hydroxysteroid dehydrogenase type 2 enzyme (11ßHSD2) results in an inefficient conversion of cortisol to cortisone, which triggers hypertension. Cytosine-adenine repeat (CA repeat) microsatellite has been associated with low HSD11B2 gene expression. AIM: To determine whether the CA-repeat length in intron 1 affect the serum cortisol to cortisone (F/E) ratio and/or blood pressure (BP) levels in pediatric subjects. SUBJECTS AND METHODS: Eighty-one hypertensive (HT) and 117 normotensive (NT) subjects participated in this study. We measured BP levels, as well as the F and E and F/E ratio in morning sera and 12-hour urine samples. The length of CA repeats was determined through fragment analysis. We compared the allele distribution between the HT and NT groups, and the patients were dichotomized into groups with short alleles (S) (<21 CA repeats) or long alleles (L), and also in groups according genotype (allele combination: S/S and S/L + L/L). RESULTS: We found no differences in the distribution of CA-repeat allelic length between the NT and HT groups (P = 0.7807), and there was no correlation between the CA-repeat allelic length and BP (P = 0.1151) levels or the serum F/E ratio (P = 0.6778). However, the serum F/E ratio was higher in the HT group than in the NT group (P = 0.0251). The serum F/E ratio was associated with systolic BP index independent of body mass index only in HT group. CONCLUSIONS: The CA-repeat length did not influence BP levels or serum F/E ratios in pediatric subjects. However, the serum F/E ratio was associated with BP, suggesting a role of 11ßHSD2 in mineralocorticoid hypertension.

Maternal high-fat diet acts as a stressor increasing maternal glucocorticoids' signaling to the fetus and disrupting maternal behavior and brain activation in C57BL/6J mice.

Maternal diet during pregnancy can impact maternal behavior as well as the intrauterine environment, playing a critical role in programming offspring's physiology. In a preliminary study, we found a strong association between high-fat diet (HFD) during pregnancy and increased cannibalistic episodes and dams' mortality during late pregnancy and parturition. Based upon these data, we hypothesized that HFD during pregnancy could negatively affect neuroendocrine and metabolic regulations occurring during the final stages of pregnancy, thereby disrupting maternal behavior. To test this hypothesis, female C57BL/6J mice were fed HFD or control diet for 11 weeks until three days before the expected delivery date. Basal corticosterone plasma levels and brain levels of c-Fos were measured both before and after delivery, in addition to leptin levels in the adipose tissue. Dam's emotional behavior and social anxiety, in addition to locomotor activity were assessed before parturition. Data show that HFD led to aberrant maternal behavior, dams being characterized by behaviors related to aggression toward an unfamiliar social stimulus in the social avoidance test, in addition to decreased locomotor activity. Neural activity in HFD dams was reduced in the olfactory bulbs, a crucial brain region for social and olfactory recognition hence essential for maternal behavior. Furthermore, HFD feeding resulted in increased circulating levels of maternal corticosterone and decreased levels of leptin. In addition, the activity of the protective 11ß-dehydrogenase-2 (11ß-HSD-2) barrier in the placenta was decreased together with 11ß-dehydrogenase-1 (11ß-HSD-1) gene expression. Overall, these data suggest that HFD acts as a stressful challenge during pregnancy, impairing the neuroendocrine system and the neural activity of brain regions involved in the processing of relevant olfactory stimuli, with negative consequences on maternal physiology and behavior.

Cross-talk between cAMP and MAPK pathways in HSD11B2 induction by hCG in placental trophoblasts.

Overexposure of the fetus to glucocorticoids in gestation is detrimental to fetal development. The passage of maternal glucocorticoids into the fetal circulation is governed by 11beta-Hydroxysteroid Dehydrogenase Type 2 (HSD11B2) in the placental syncytiotrophoblasts. Human chorionic gonadotropin (hCG) plays an important role in maintaining placental HSD11B2 expression via activation of the cAMP pathway. In this study, we investigated the relationship between the activation of the cAMP pathway by hCG and subsequent phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) or p38 mitogen-activated protein kinase (MAPK) pathways in the regulation of placental HSD11B2 expression in human placental syncytiotrophoblasts. We found that treatment of the placental syncytiotrophoblasts with either hCG or dibutyl cAMP (dbcAMP) could promote the phosphorylation of p38 and ERK1/2. Inhibition of p38 MAPK with SB203580 not only reduced the basal HSD11B2 mRNA and protein levels but also attenuated HSD11B2 levels induced by either hCG or dbcAMP. By contrast, inhibition of ERK1/2 with PD98059 increased the basal mRNA and protein levels of HSD11B2 and had no effect on HSD11B2 mRNA and protein levels induced by either hCG or dbcAMP. These data suggest that p38 MAPK is involved in both basal and hCG/cAMP-induced expression of HSD11B2, and ERK1/2 may play a role opposite to p38 MAPK at least in the basal expression of HSD11B2 in human placental syncytiotrophoblasts and that there is complicated cross-talk between hCG/cAMP and MAPK cascades in the regulation of placental HSD11B2 expression.

Preeclampsia induced by cadmium in rats is related to abnormal local glucocorticoid synthesis in placenta.

BACKGROUND: Cadmium (Cd) is a major environmental pollutant that causes multiple adverse health effects in humans and animals. In this study, we investigated Cd-mediated toxic effects in rats during pregnancy and endocrine intervention in the placenta. METHODS: We exposed pregnant rats to intraperitoneal Cd (CdCl2) at various doses (0, 0.25, and 0.5 mg/kg BW/day) from days 5 to 19 of pregnancy and evaluated the maternal-placental-fetal parameters linked to preeclampsia. We measured the corticosterone level in rat serum and placental tissue by sensitive ELISA and also analyzed the expression of glucocorticoid synthesis enzymes in the placenta. RESULTS: Key features of preeclampsia (PE), including hypertension, proteinuria, glomerular endotheliosis, placental abnormalities and small fetal size, appeared in pregnant rats after injection with 0.5 mg/kg BW/day Cd. The placental corticosterone production and maternal and fetal plasma corticosterone levels were increased in rats treated with 0.5 mg/kg BW/day Cd (P <0.01). The expression of 21-hydroxylase (CYP21) and 11beta-hydroxylase (CYP11B1), enzymes essential for corticosteroid synthesis, were increased in Cd-exposed placenta (P <0.01). 11beta-hydroxysteroid dehydrogenase (11beta-HSD2), a dominant negative regulator of local glucocorticoid levels, was decreased in Cd-exposed placenta (P <0.01). CONCLUSIONS: Our study demonstrates for the first time that changes in placental glucocorticoid synthesis induced by Cd exposure during pregnancy could contribute to preeclamptic conditions in rats.

Differential expression of 11ß-hydroxysteroid dehydrogenase type 1 and 2 in mild and moderate/severe persistent allergic nasal mucosa and regulation of their expression by Th2 cytokines: asthma and rhinitis.

BACKGROUND: Glucocorticoids are used to treat allergic rhinitis, but the mechanisms by which they induce disease remission are unclear. 11ß-hydroxysteroid dehydrogenase (11ß-HSD) is a tissue-specific regulator of glucocorticoid responses, inducing the interconversion of inactive and active glucocorticoids. OBJECTIVE: We analysed the expression and distribution patterns of 11ß-HSD1, 11ß-HSD2, and steroidogenic enzymes in normal and allergic nasal mucosa, and cytokine-driven regulation of their expression. The production levels of cortisol in normal, allergic nasal mucosa and in cultured epithelial cells stimulated with cytokines were also determined. METHODS: The expression levels of 11ß-HSD1, 11ß-HSD2, steroidogenic enzymes (CYP11B1, CYP11A1), and cortisol in normal, mild, and moderate/severe persistent allergic nasal mucosa were assessed by real-time PCR, Western blot, immunohistochemistry, and ELISA. The expression levels of 11ß-HSD1, 11ß-HSD2, CYP11B1, CYP11A1, and cortisol were also determined in cultured nasal epithelial cell treated with IL-4, IL-5, IL-13, IL-17A, and IFN-γ. Conversion ratio of cortisone to cortisol was evaluated using siRNA technique, 11ß-HSD1 inhibitor, and the measurement of 11ß-HSD1 activity. RESULTS: The expression levels of 11ß-HSD1, CYP11B1, and cortisol were up-regulated in mild and moderate/severe persistent allergic nasal mucosa. By contrast, 11ß-HSD2 expression was decreased in allergic nasal mucosa. In cultured epithelial cells treated with IL-4, IL-5, IL-13, and IL-17A, 11ß-HSD1 expression and activity increased in parallel with the expression levels of CYP11B1 and cortisol, but the production of 11ß-HSD2 decreased. CYP11A1 expression level was not changed in allergic nasal mucosa or in response to stimulation with cytokines. SiRNA technique or the measurement of 11ß-HSD1 activity showed that nasal epithelium activates cortisone to cortisol in a 11ß-HSD-dependent manner. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicate that the localized anti-inflammatory effects of glucocorticoids are regulated by inflammatory cytokines, which can modulate the expression of 11ß-HSD1, 11ß-HSD2, and CYP11B1, and by the intracellular concentrations of bioactive glucocorticoids.

Cholestatic pregnancy is associated with reduced placental 11ßHSD2 expression.

INTRODUCTION: Intrahepatic Cholestasis of Pregnancy (ICP) is associated with an increased risk of fetal morbidity and mortality and is characterised by elevated bile acids in the maternal and fetal compartments. Bile acids have been shown to attenuate renal 11ßHSD2 expression and, given the protective role of placental 11ßHSD2 in preventing fetal exposure to excessive maternal cortisol, we aimed to establish whether raised serum bile acids in ICP influence placental 11ßHSD2 expression. METHODS: Placental tissue from human and murine cholestatic pregnancy was evaluated for changes in 11ßHSD2 mRNA expression compared to uncomplicated pregnancy using quantitative PCR. Parallel in vitro studies were performed using BeWo choriocarcinoma cells to assess the effect of different bile acid species on 11ßHSD2 gene expression and whether concurrent UDCA administration can reverse any bile acid induced changes. RESULTS: Placental 11ßHSD2 mRNA expression was reduced in human and murine cholestatic pregnancy. In BeWo cells, treatment with the primary bile acid CDCA resulted in reduced 11ßHSD2 gene expression, while treatment with other primary bile acids had no significant effect. Furthermore, the tertiary bile acid UDCA, used in the treatment of ICP did not significantly affect 11ßHSD2 mRNA levels either alone, or when co-administered with CDCA. DISCUSSION: Under cholestatic conditions placental 11ßHSD2 mRNA is reduced. Studies in BeWo choriocarcinoma cells demonstrated that CDCA is likely to be the specific bile acid that mediates this effect. UDCA, the main bile acid used to treat cholestasis, did not reduce placental 11ßHSD2 expression, further supporting its use in the management of ICP.

Expression of 11ß-hydroxysteroid dehydrogenase type 2 is deregulated in colon carcinoma.

Although the effects of glucocorticoids on proliferation, differentiation and apoptosis are well known, and steroid hormones have been identified to play a role in pathogenesis and the development of various cancers, limited data are available regarding the relationship between the local metabolism of glucocorticoids and colorectal adenocarcinoma (CRC) formation. Glucocorticoid metabolism is determined by 11ß-hydroxysteroid dehydrogenases type 1 and 2 (11HSD1, 11HSD2), which increase the local concentration of cortisol due to the reduction of cortisone, or decrease this concentration due to the oxidation of cortisol. The objective of this study was to evaluate the extent of 11HSD1 and 11HSD2 mRNA in pre-malignant colorectal polyps and in CRC. The specimens were retrieved from patients by endoscopic or surgical resection and the expression of 11HSD1 and 11HSD2 was measured by real-time PCR. The polyps were of the following histological types: hyperplastic polyps and adenomas with low- or high-grade dysplasia. The neoplastic tissue of CRC obtained during tumor surgery was also studied. It was found that 11HSD2 was not only downregulated in CRC but already in the early stages of neoplastic transformation (adenoma with low-grade dysplasia). In contrast, the level of 11HSD1 was significantly increased in CRC but not in pre-malignant polyps. The results demonstrate that the downregulation of 11HSD2 gene expression is a typical feature of the development of colorectal polypous lesions and their transformation into CRC.

Postdate pregnancy: changes of placental/membranes 11ß-hydroxysteroid dehydrogenase mRNA and activity.

11ß-Hydroxysteroid dehydrogenase 1 and 2 (11ß-HSD1 and 11ß-HSD2) are involved in the complex mechanism of human parturition. The present study examined mRNA expression and activity of membrane 11ß-HSD1 and placental 11ß-HSD2 in postdate pregnancies according to response of labor induction. In comparison to postdate women who had spontaneous delivery or after induction the non-responders showed significantly low c and high 11ß-HSD2 expression and activity These data suggest that disrupted expression and activity of 11ß-HSDs may occur in some postdate pregnancies.

Levels of inflammatory cytokines, adrenal steroids, and mRNA for GRα, GRß and 11ßHSD1 in TB pleurisy.

Our previous work on the immune-endocrine features of patients with pulmonary tuberculosis (TB) showed markedly decreased plasma levels of dehydroepiandrosterone (DHEA) together with augmented concentrations of Cortisol and pro- and anti-inflammatory cytokines. Studies in peripheral blood mononuclear cells (PBMC) indicated a lower mRNA α/ß ratio of glucocorticoid receptors -GR- together with a higher 11ß-hydroxysteroid dehydrogenase type 1 (11ßHSD1) mRNA expression in cases with severe pulmonary TB. Since Pleural TB (PLTB) is a rather benign manifestation of TB, we now analyzed the systemic and local immune-endocrine profile as well as the GRα, GRß, 11ßHSD1 and 11ßHSD2 transcripts in PBMC and pleural effusion mononuclear cells (PEMC) of patients with PLTB. PLTB patients had increased levels of IL-1ß, IL-6 and IFNγ together with reduced Cortisol and DHEA concentrations in pleural fluids. Also, a significantly increased expression of 11ßHSD1 and GRα was found in PEMC compared to PBMC. Findings point out to an appropriate immune response and a substantial inflammatory reaction, wherein the low Cortisol concentrations may be equally effective, because of the increased expression of GRα and 11ßHSD1 transcripts which may optimize the immunomodulatory properties of Cortisol.

Luteoprotective roles of luteinizing hormone are mediated by not only progesterone production but also glucocorticoid conversion in bovine corpus luteum.

Luteinizing hormone (LH) is known as a key regulator of corpus luteum (CL) function, but the luteoprotective mechanisms of LH in the maintenance of bovine CL function are not well understood. The current study investigated if LH increases cell viability and induces cortisol conversion, and if the luteoprotective action of LH is mediated by stimulating the local production and action of progesterone (P4) and/or cortisol. Cultured bovine luteal cells obtained at the mid-luteal stage (Days 8-12 of the estrous cycle) were treated for 24 hr with LH (10 ng/ml) with/without onapristone (OP, a specific P4 receptor antagonist; 100 µM), cortisone (1 µM), and aminoglutethimide (AGT, a specific inhibitor of cytochrome P450 side-chain cleavage; 100 µM). LH with and without OP significantly increased the mRNA and protein expressions of 11ß-hydroxysteroid dehydrogenase (HSD11B) 1, but did not affect the mRNA or protein expression of HSD11B2. These treatments also significantly increased HSD11B1 activity. Cell viability was significantly increased by LH alone or by LH in combination with cortisone and OP. LH in combination with OP or AGT significantly decreased cell viability as compared to LH alone. The overall results suggest that LH stimulates not only P4 production but also HSD11B1 expression, thereby increasing the cortisol concentration in the bovine CL, and that LH prevents cell death through these survival pathways. LH may consequently support CL function during the luteal phase in cattle.

Abnormal fetomaternal glucocorticoid metabolism in the background of premature delivery: placental expression patterns of the 11ß-hydroxysteroid dehydrogenase 2 gene.

OBJECTIVE: During pregnancy, 11ß-hydroxysteroid dehydrogenase 2 (11ß-HSD2) is involved in the development of the placental barrier, and its main function is to protect the fetus from the effects of the physiological increase of maternal glucocorticoids. We compared human placental gene expression patterns of 11ß-HSD2 from pregnancies that ended with preterm delivery versus full term pregnancies as controls. STUDY DESIGN: We used real-time PCR to assess the placental gene expression patterns of 11ß-HSD2 in 104 preterm and 140 full term pregnancies (control group) at the time of delivery. RESULTS: In the preterm delivery group, the proportion of smokers was 26.9%, significantly higher than in the control group. Preterm delivery began with premature rupture of membranes in 70.2% and spontaneous uterine activity in 29.8%. The 11ß-HSD2 gene was underexpressed in the preterm delivery group compared to normal pregnancy between 28 and 36 gestational weeks, but unchanged between 24 and 28 weeks. There was no fetal gender effect on 11ß-HSD2 gene expression. CONCLUSION: The reduced activity of the 11ß-HSD2 gene seen in the preterm delivery group may impair fetal defences against maternal glucocorticoid exposure. In cases of impending premature delivery, glucocorticoid effects, potentially including postnatal neurological abnormalities and growth restriction, may be worsened by prophylactic steroids given to accelerate fetal lung maturity. The impairment in fetal defences against maternal glucocorticoids due to reduced 11ß-HSD2 enzyme activity appears to begin after gestational week 28.

Sex specific changes in placental growth and MAPK following short term maternal dexamethasone exposure in the mouse.

OBJECTIVES: Maternal glucocorticoid (GC) exposure during pregnancy can alter fetal development and program the onset of disease in adult offspring. The placenta helps protect the fetus from excess GC exposure but is itself susceptible to maternal insults and may be involved in sex dependant regulation of fetal programming. This study aimed to investigate the effects of maternal GC exposure on the developing placenta. STUDY DESIGN AND MAIN OUTCOME MEASURES: Pregnant mice were treated with dexamethasone (DEX-1 µg/kg/h) or saline (SAL) for 60 h via minipump beginning at E12.5. Placentas were collected at E14.5 and E17.5 and the expression of growth factors and placental transporters examined by real-time PCR and/or Western blot. Histological analysis was performed to assess for morphological changes. RESULTS: At E14.5, DEX exposed male and female fetuses had a lower weight compared to SAL animals but placental weight was lower in females only. Hsd11b2 and Vegfa gene expression was increased and MAPK1 protein expression decreased in the placentas of females only. At E17.5 placental and fetal body weights were similar and differences in MAPK were no longer present although HSD11B2 protein was elevated in placentas of DEX females. Levels of glucose or amino acid transporters were unaffected. CONCLUSIONS: Results suggest sex specific responses to maternal GCs within the placenta. Decreased levels of MAPK protein in placentas of female fetuses suggest alterations in the MAPK pathway may contribute to the lower placental weights in this sex. This may contribute towards sex specific fetal programming of adult disease.

Mineralocorticoid receptor expression in human venous smooth muscle cells: a potential role for aldosterone signaling in vein graft arterialization.

Experimental studies have suggested a role for the local renin-angiotensin-aldosterone system in the response to vascular injury. Clinical data support that aldosterone, via activation of the mineralocorticoid receptor (MR), is an important mediator of vascular damage in humans with cardiovascular disease. In mineralocorticoid-sensitive target tissue, aldosterone specificity for MR is conferred enzymatically by the cortisol-inactivating enzyme 11ß-hydroxysteroid-dehydrogenase-2 (11ßHSD2). However, the role of MR/aldosterone signaling in the venous system has not been explored. We hypothesized that MR expression and signaling in venous smooth muscle cells contributes to the arterialization of venous conduits and the injury response in vein bypass grafts. MR immunostaining was observed in all samples of excised human peripheral vein graft lesions and in explanted experimental rabbit carotid interposition vein grafts, with minimal staining in control greater saphenous vein. We also found upregulated transcriptional expression of both MR and 11ßHSD2 in human vein graft and rabbit vein graft, whereas control greater saphenous vein expressed minimal MR and no detectable 11ßHSD2. The expression of MR and 11ßHSD2 was confirmed in cultured human saphenous venous smooth muscle cells (hSVSMCs). Using an adenovirus containing a MR response element-driven reporter gene, we demonstrate that MR in hSVSMCs is capable of mediating aldosterone-induced gene activation. The functional significance for MR signaling in hSVSMCs is supported by the aldosterone-induced increase of angiotensin II type-1 receptor gene expression that was inhibited by the MR antagonist spironolactone. The upregulation of MR and 11ßHSD2 suggests that aldosterone-mediated tissue injury plays a role in vein graft arterialization.

Glucocorticoid receptor stimulation and the regulation of neonatal cerebellar neural progenitor cell apoptosis.

Glucocorticoids are used to treat respiratory dysfunction associated with premature birth but have been shown to cause neurodevelopmental deficits when used therapeutically. Recently, we established that acute glucocorticoid exposure at clinically relevant doses produces neural progenitor cell apoptosis in the external granule layer of the developing mouse cerebellum and permanent decreases in the number of cerebellar neurons. As the cerebellum naturally matures and neurogenesis is no longer needed, the external granule layer decreases proliferation and permanently disappears during the second week of life. At this same time, corticosterone (the endogenous rodent glucocorticoid) release increases and a glucocorticoid-metabolizing enzyme that protects the external granule layer against glucocorticoid receptor stimulation (11ß-Hydroxysteroid-Dehydrogenase-Type 2; HSD2) naturally disappears. Here we show that HSD2 inhibition and raising corticosterone to adult physiological levels both can independently increase neural progenitor cell apoptosis in the neonatal mouse. Conversely, glucocorticoid receptor antagonism decreases natural physiological apoptosis in this same progenitor cell population suggesting that endogenous glucocorticoid stimulation may regulate apoptosis in the external granule layer. We also found that glucocorticoids which HSD2 can effectively metabolize generate less external granule layer apoptosis than glucocorticoids this enzyme is ineffective at breaking down. This finding may explain why glucocorticoids that this enzyme can metabolize are clinically effective at treating respiratory dysfunction yet seem to produce no neurodevelopmental deficits. Finally, we demonstrate that both acute and chronic glucocorticoid exposures produce external granule layer apoptosis but without appropriate control groups this effect becomes masked. These results are discussed in terms of their implications for glucocorticoid therapy and neurodevelopment during the perinatal period.

Age-related changes in corticosteroid receptor expression and monoamine neurotransmitter concentrations in various brain regions of postnatal pigs.

Negative early life experience may be associated with altered functioning of stress-related systems and may increase vulnerability to diseases later in life. Corticosteroids are important mediators of homeostasis and stress and exert their effects via two receptors, the mineralocorticoid receptor (MR) and the glucocorticoid receptor (GR), and through the glucocorticoid-metabolizing enzymes 11ß-hydroxysteroid dehydrogenase (11ß-HSD) types 1 and 2 in a brain-region-specific manner. However, relatively little is known about the postnatal ontogeny of these receptors and enzymes in the central nervous system. Here we describe, for the first time, the postnatal ontogeny of central GR, MR, 11ß-HSD1, and 11ß-HSD2 gene expression and monoamine levels in stress-related brain regions of domestic pigs at 7, 21, and 35 days of age. During the postnatal period, there was an increase in GR, MR, and 11ß-HSD1 mRNA expression in the pituitary and prefrontal cortex and an increase in MR mRNA expression in the hippocampus. We also demonstrated age-dependent changes in levels of noradrenaline and dopamine and their metabolites in the locus coeruleus, with the highest concentrations on day 7 compared with days 21 and 35. In conclusion, the dynamic changes in corticosteroid receptors and monoamines during neural development of postnatal pigs may represent periods of sensitivity to environmental stress that are comparable to some extent with those that are observed in primates and humans. Thus, these findings support the use of the domestic pig as an alternative animal model for humans in stress research.