Early life corticosteroid overexposure: Epigenetic and fetal origins of adult diseases.

The relationship between events occurring during intrauterine development and later-life predisposition to long-term disease, has been described. The fetus responds to excess intrauterine exposure to high levels of corticosteroids, modifying their physiological development and stopping their growth. Fetal exposure to elevated levels of either endogenous (alterations in fetal hypothalamic-pituitary-adrenal axis) or synthetic corticosteroids, is one model of early-life adversity; to developing adult disease. At the molecular level, there are transcriptional changes in metabolic and growth pathways. Epigenetic mechanisms participate in transgenerational inheritance, not genomic. Exposures that change 11ß-hydroxysteroid dehydrogenase type 2 enzyme methylation status in the placenta can result in transcriptional repression of the gene, causing the fetus to be exposed to higher levels of cortisol. More precise diagnosis and management of antenatal corticosteroids for preterm birth, would potentially decrease the risk of long-term adverse outcomes. More studies are needed to understand the potential roles of factors to alter fetal corticosteroid exposure. Long-term infant follow-up is required to determine whether methylation changes in placenta may represent useful biomarkers of later disease risk. This review, summarize recent advances in the programming of fetal effects of corticosteroid exposure, the role of corticosteroids in epigenetic gene regulation of placental 11ß-hydroxysteroid dehydrogenase type 2 enzyme expression and transgenerational effects.

In vitro methods to assess 11ß-hydroxysteroid dehydrogenase type 2 activity.

11ß-Hydroxysteroid dehydrogenase type 2 (11ß-HSD2) converts active 11ß-hydroxyglucocorticoids to their inactive 11-keto forms, fine-tuning the activation of mineralocorticoid and glucocorticoid receptors. 11ß-HSD2 is expressed in mineralocorticoid target tissues such as renal distal tubules and cortical collecting ducts, and distal colon, but also in placenta where it acts as a barrier to reduce the amount of maternal glucocorticoids that reach the fetus. Disruption of 11ß-HSD2 activity by genetic defects or inhibitors causes the syndrome of apparent mineralocorticoid excess (AME), characterized by hypernatremia, hypokalemia and hypertension. Secondary hypertension due to 11ß-HSD2 inhibition has been observed upon consumption of excessive amounts of licorice and in patients treated with the azole fungicides posaconazole and itraconazole. Furthermore, inhibition of 11ß-HSD2 during pregnancy with elevated exposure of the fetus to cortisol can cause neurological complications with a lower intelligence quotient, higher odds of attention deficit and hyperactivity disorder as well as metabolic reprogramming with an increased risk of cardio-metabolic disease in adulthood. This chapter describes in vitro methods for the determination of 11ß-HSD2 activity that can be applied to identify inhibitors that may cause secondary hypertension and characterize the enzyme's activity in disease models. The included decision tree and the list of methods with their advantages and disadvantages aim to enable the reader to select and apply an in vitro method suitable for the scientific question and the equipment available in the respective laboratory.

Maternal High-Fructose Corn Syrup Intake Impairs Corticosterone Clearance by Reducing Renal 11ß-Hsd2 Activity via miR-27a-Mediated Mechanism in Rat Offspring.

We previously reported that maternal fructose consumption increases blood corticosterone levels in rat offspring. However, the underlying mechanism of action remains unclear. In the present study, we aimed to elucidate the molecular mechanism by which maternal high-fructose corn syrup (HFCS) intake increases circulating GC levels in rat offspring (GC; corticosterone in rodents and cortisol in humans). Female Sprague Dawley rats received HFCS solution during gestation and lactation. The male offspring were fed distilled water from weaning to 60 days of age. We investigated the activities of GC-metabolizing enzymes (11ß-Hsd1 and 11ß-Hsd2) in various tissues (i.e., liver, kidney, adrenal glands, muscle, and white adipose tissue) and epigenetic modification. 11ß-Hsd2 activity decreased in the kidney of the HFCS-fed dams. Moreover, the epigenetic analysis suggested that miR-27a reduced Hsd11b2 mRNA expression in the kidney of offspring. Maternal HFCS-induced elevation of circulating GC levels in offspring may be explained by a decrease in 11ß-Hsd2 activity via renal miR-27a expression. The present study may allow us to determine one of the mechanisms of GC elevation in rat offspring that is often observed in the developmental origins of the health and disease (DOHaD) phenomenon.

Down-Regulation of the Mineralocorticoid Receptor (MR) and Up-Regulation of Hydroxysteroid 11-Beta Dehydrogenase Type 2 (HSD11B2) Isoenzyme in Critically Ill Patients.

Objective: The mineralocorticoid receptor (MR) has two ligands, aldosterone and cortisol. Hydroxysteroid 11-beta dehydrogenase (HSD11B) isoenzymes regulate which ligand will bind to MR. In this study we aimed to evaluate the expression of the MR and the HSD11B isozymes in peripheral polymorphonuclear cells (PMNs) in critical illness for a 13-day period.Design: Prospective studySetting: One multi-disciplinary intensive care unit (ICU)Participants: Forty-two critically ill patientsMethods: Messenger RNA (mRNA) expression of MR, HSD11B1, and HSD11B2, aldosterone levels, and plasma renin activity (PRA) were measured in 42 patients on ICU admission and on days 4, 8, and 13. Twenty-five age and sex-matched healthy subjects were used as controls.Results: Compared to healthy controls, MR expression in critically ill patients was lower during the entire study period. HSD11B1 expression was also lower, while HSD11B2 expression was higher. In patients, PRA, aldosterone, the aldosterone:renin ratio, and cortisol remained unaltered during the study period.Conclusion: Our results suggest that, in our cohort of critically ill patients, local endogenous cortisol availability is diminished, pointing towards glucocorticoid resistance. Aldosterone probably occupies the MR, raising the possibility that PMNs might be useful to study to gain insights into MR functionality during pathological states.

Comparative study on the gene expression of corticosterone metabolic enzymes in embryonic tissues between Tibetan and broiler chickens.

Glucocorticoids (GCs) are an essential mediator hormone that can regulate animal growth, behavior, the phenotype of offspring, and so on, while GCs in poultry are predominantly corticosterones. The biological activity of GCs is mainly regulated by the intracellular metabolic enzymes, including 11ß-hydroxysteroid dehydrogenases 1 (11ß-HSD1), 11ß-hydroxysteroid dehydrogenases 2 (11ß-HSD2), and 20-hydroxysteroid dehydrogenase (20-HSD). To investigate the embryonic mechanisms of phenotypic differences between breeds, we compared the expression of corticosterone metabolic enzyme genes in the yolk-sac membrane and chorioallantoic membrane (CAM). We described the tissue distribution and ontogenic patterns of corticosterone metabolic enzymes during embryonic incubation between Tibetan and broiler chickens. Forty fertilized eggs from Tibetan and broiler chickens were incubated under hypoxic and normoxic conditions, respectively. Real-time fluorescence quantitative PCR was used to examine the expression of 11ß-HSD1/2, and 20-HSD mRNA in embryonic tissues. The results showed that the expression levels of yolk-sac membrane mRNA of 11ß-HSD2 and 20-HSD in Tibetan chickens on E14 (embryonic day of 14) were significantly lower than those of broiler chickens (P < 0.05), and these genes expression of CAM in Tibetan chickens were higher than those of broiler chickens (P < 0.05). In addition, the three genes in the yolk-sac membrane and CAM were followed by a down-regulation on E18 (embryonic day of 18). The 11ß-HSD1 and 11ß-HSD2 genes followed a similar tissue-specific pattern: the expression level was more abundantly in the liver, kidney, and intestine, with relatively lower abundance in the hypothalamus and muscle, and the expression level of 20-HSD genes in all tissues tested was higher. In the liver, 20-HSD of both Tibetan and broiler chickens showed different ontogeny development patterns, and hepatic mRNA expression of 20-HSD in broiler chickens was significantly higher than that of Tibetan chickens of the same age from E14 to E18 (P < 0.05). This study preliminarily revealed the expression levels of cortisol metabolic genes in different tissues during the development process of Tibetan and broiler chicken embryos. It provided essential information for in-depth research of the internal mechanism of maternal GCs programming on offspring.

Cholic acid exposure during late pregnancy causes placental dysfunction and fetal growth restriction by reactive oxygen species-mediated activation of placental GCN2/eIF2α pathway.

Epidemiological studies suggest that fetal growth restriction (FGR) caused by gestational cholestasis is associated with elevated serum cholic acid (CA). Here, we explore the mechanism by which CA induces FGR. Pregnant mice except controls were orally administered with CA daily from gestational day 13 (GD13) to GD17. Results found that CA exposure decreased fetal weight and crown-rump length, and increased the incidence of FGR in a dose-dependent manner. Furthermore, CA caused placental glucocorticoid (GC) barrier dysfunction via down-regulating the protein but not the mRNA level of placental 11ß-Hydroxysteroid dehydrogenase-2 (11ß-HSD2). Additionally, CA activated placental GCN2/eIF2α pathway. GCN2iB, an inhibitor of GCN2, significantly inhibited CA-induced down-regulation of 11ß-HSD2 protein. We further found that CA caused excessive reactive oxygen species (ROS) production and oxidative stress in mouse placentas and human trophoblasts. NAC significantly rescued CA-induced placental barrier dysfunction by inhibiting activation of GCN2/eIF2α pathway and subsequent down-regulation of 11ß-HSD2 protein in placental trophoblasts. Importantly, NAC rescued CA-induced FGR in mice. Overall, our results suggest that CA exposure during late pregnancy induces placental GC barrier dysfunction and subsequent FGR may be via ROS-mediated placental GCN2/eIF2α activation. This study provides valuable insight for understanding the mechanism of cholestasis-induced placental dysfunction and subsequent FGR.

Phthalates cause a low-renin phenotype commonly found in premature infants with idiopathic neonatal hypertension.

Since the 1970s, when the initial reports of neonatal hypertension related to renal artery thromboembolism were published, other secondary causes of neonatal hypertension have been reported. Those infants with no identifiable cause of hypertension were labeled with a variety of terms. Herein, we describe such infants as having idiopathic neonatal hypertension (INH). Most, but not all, of these hypertensive infants were noted to have bronchopulmonary dysplasia (BPD). More recently, reports described common clinical characteristics seen in INH patients, whether or not they had BPD. This phenotype includes low plasma renin activity, presentation near 40 weeks postmenstrual age, and a favorable response to treatment with spironolactone. A small prospective study in INH patents showed evidence of mineralocorticoid receptor activation due to inhibition of 11ß-HSD2, the enzyme that converts cortisol to the less potent mineralocorticoid-cortisone. Meanwhile, phthalate metabolites have been shown to inhibit 11ß-HSD2 in human microsomes. Premature infants can come in contact with exceptionally large phthalate exposures, especially those infants with BPD. This work describes a common low-renin phenotype, commonly seen in patients categorized as having INH. Further, we review the evidence that hypertension in INH patients with the low-renin phenotype may be mediated by phthalate-associated inhibition of 11ß-HSD2. Lastly, we review the implications of these findings regarding identification, treatment, and prevention of the low-renin hypertension phenotype seen in premature infants categorized as having INH.

The effect of cold exposure on the levels of glucocorticoids, 11-hydroxysteroid dehydrogenase 2, and placental vascularization in a rat model.

OBJECTIVE: Cold exposure (CE) before birth is one of the initial stressors that may impact mammalian pregnancy, changing placental and fetal development and affecting the health of the offspring. While glucocorticoids (GCs) participate in the body's response to the stress of CE, the specific mechanisms of their action are unclear. This study aims to determine the effect of CE stress on the placenta and to test whether stress, caused by cold exposure in pregnancy impairs fetal development by changing placental angiogenesis via excessive GC expression. MATERIALS AND METHODS: CE rat model was created by exposing 30 SD rats to cold preconception, or during the first, second, and third weeks of pregnancy. Serum cortisol and soluble fms-like tyrosine kinase-1 (sFlt-1) expression levels, physiological index changes (food intake, body weight change and blood pressure), and pregnancy outcomes (fetal rat weight, number of live fetal rats, and placental weight) were collected at baseline and at different time points after the conception. Protein expression levels of 11 ß-hydroxysteroid dehydrogenase 2 (11ß-HSD2), glucocorticoid receptor, vascular endothelial growth factor A (VEGF-A), placental growth factor (PIGF), and sFlt-1 in placental tissues were measured by western blotting. Cytokeratin (CK) and laminin (LN) in trophoblasts, and α-actin in vascular smooth muscle of the spiral arteries of pregnant rats after the systemic cold treatment were assessed by immunofluorescence and visualized by fluorescent microscopy. To test the effect of 11ß-HSD2 levels on the placental recasting, human first-trimester extravillous trophoblast cells (HTR8/SVneo) underwent knockdown using specific 11ß-HSD2 siRNA constructs.  Expression levels of 11ß-HSD2 were analyzed by quantitative real-time PCR (qPCR) and into HTR8 cells, and the expression levels of the 11ß-HSD2 gene in each group were measured using qPCR. Cell migration and invasion was assessed by Transwell migration assay, and sFlt-1 levels in HTR8 cells were measured by ELISA. RESULTS: CE pre-conception led to consistently increasing serum corticosterone and sFlt-1 levels throughout pregnancy, and persistently increased diastolic blood pressure (DBP) in rat CE model compared to control animals. CE during the second week of gestation (Gp.3) was associated with significantly lower placental weight (p=0.0003). Cold exposure in the third week (Gp.4) was associated with significantly (p=0.001) lower fetal weight. CE pre-conception was associated with significantly decreased placental levels of 11ß-HSD2, glucocorticoid receptor, VEGF-A, PIGF, and sFlt-1 proteins and α-actin compared to the control group. Silencing 11ß-HSD2 by siRNA led to reduced cell migrations and invasion, and markedly increased expression levels of sFlt-1 in HTR8/SVneo cells (p<0.05). CONCLUSIONS: Pre-conception cold exposure and during early pregnancy leads to increased GCs levels and impaired placental 11ß-HSD2 activity. We suggest that the subsequent 11ß-HSD2-induced increase in the sFlt-1expression during early pregnancy may affect placental vascular remodeling and change placental morphological structure and function.

Apparent mineralocorticoid excess: comprehensive overview of molecular genetics.

Apparent mineralocorticoid excess is an autosomal recessive form of monogenic disease characterized by juvenile resistant low-renin hypertension, marked hypokalemic alkalosis, low aldosterone levels, and high ratios of cortisol to cortisone metabolites. It is caused by defects in the HSD11B2 gene, encoding the enzyme 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), which is primarily involved in the peripheral conversion of cortisol to cortisone. To date, over 50 deleterious HSD11B2 mutations have been identified worldwide. Multiple molecular mechanisms function in the lowering of 11ß-HSD2 activity, including damaging protein stability, lowered affinity for the substrate and cofactor, and disrupting the dimer interface. Genetic polymorphism, environmental factors as well as epigenetic modifications may also offer an implicit explanation for the molecular pathogenesis of AME. A precise diagnosis depends on genetic testing, which allows for early and specific management to avoid the morbidity and mortality from target organ damage. In this review, we provide insights into the molecular genetics of classic and non-classic apparent mineralocorticoid excess and aim to offer a comprehensive overview of this monogenic disease.

Maternal glucocorticoids do not directly mediate the effects of maternal social stress on the fetus.

Stress during pregnancy negatively affects the fetus and increases the risk for affective disorders in adulthood. Excess maternal glucocorticoids are thought to mediate fetal programming; however, whether they exert their effects directly or indirectly remains unclear. During pregnancy, protective mechanisms including maternal hypothalamic-pituitary-adrenal (HPA) axis hyporesponsiveness and placental 11ß-hydroxysteroid dehydrogenase (11ßHSD) type 2, which inactivates glucocorticoids, limit mother-to-fetus glucocorticoid transfer. However, whether repeated stress negatively impacts these mechanisms is not known. Pregnant rats were exposed to repeated social stress on gestational days (GD) 16-20 and several aspects of HPA axis and glucocorticoid regulation, including concentrations of glucocorticoids, gene expression for their receptors (Nr3c1, Nr3c2), receptor chaperones (Fkbp51, Fkbp52) and enzymes that control local glucocorticoid availability (Hsd11b1, Hsd11b2), were investigated in the maternal, placental and fetal compartments on GD20. The maternal HPA axis was activated following stress, though the primary driver was vasopressin, rather than corticotropin-releasing hormone. Despite the stress-induced increase in circulating corticosterone in the dams, only a modest increase was detected in the circulation of female fetuses, with no change in the fetal brain of either sex. Moreover, there was no change in the expression of genes that mediate glucocorticoid actions or modulate local concentrations in the fetal brain. In the placenta labyrinth zone, stress increased Hsd11b2 expression only in males and Fkbp51 expression only in females. Our results indicate that any role glucocorticoids play in fetal programming is likely indirect, perhaps through sex-dependent alterations in placental gene expression, rather than exerting effects via direct crossover into the fetal brain.

Sufentanil alleviates pre-eclampsia via silencing microRNA-24-3p to target 11ß-Hydroxysteroid dehydrogenase type 2.

Pre-eclampsia (PE) is a prevalent pregnancy disease characterized by insufficient trophoblast cell migration (HTR8/SVneo). Consequently, accelerating trophoblast cell proliferation might ameliorate PE. This study assessed the effects and molecular mechanisms of Sufentanil (SUF) on HTR8/SVneo cells proliferation. HTR8/SVneo cells and PE clinical samples were used. Peripheral blood was collected from PE patients' samples, and microRNA (miR)-24-3p and 11ß-hydroxysteroid dehydrogenase type 2 (HSD11B2) was analyzed in the blood and cells. HTR8/SVneo cells were treated with varying SUF concentrations or transfected with miR-24-3p mimics/inhibitors, or HSD11B2 elevation vector. CCK-8, colony formation, transwell, and flow cytometry assays were then carried out. Association of miR-24 - 3p with HSD11B2 was investigated. PE animal model was constructed using Wistar rats to verify SUF's role on PE in vivo. According to the results, SUF boosted HTR8/SVneo cell proliferation, and inhibited miR-24-3p to accelerate HSD11B2. MiR-24-3p was increased in PE, while HSD11B2 was inhibited, and miR-24-3p targeted HSD11B2. HSD11B2 reversed miR-24-3p's repression on HTR/SVneo cell advancement. SUF restrained PE's progression in vivo and in vitro via mediating the miR-24-3p/HSD11B2 axis. In conclusion, SUF enhances HSD11B2 via repressing miR-24-3p, thereby suppressing PE's progression. The study provides an insight into the possibility of using SUF as a novel therapeutic target for PE, which acts via combining with miR-24-3p.

Intrauterine programming of cartilaginous 11ß-HSD2 induced by corticosterone and caffeine mediated susceptibility to adult osteoarthritis.

Our previous study reported that prenatal caffeine exposure (PCE) could induce chondrodysplasia and increase the susceptibility to osteoarthritis in offspring rats. However, the potential mechanisms and initiating factors remain unknown. This study aims to investigate whether 11ß-HSD2, a glucocorticoid-metabolizing enzyme, is involved in the susceptibility of osteoarthritis induced by PCE and to further explore its potential mechanisms and initiating factors. Firstly, we found that PCE reduced cartilage matrix synthesis (aggrecan/Col2a1 expression) in male adult offspring rats and exhibited an osteoarthritis phenotype following chronic stress, which was associated with persistently reduced H3K9ac and H3K27ac levels at the promoter of 11ß-HSD2 as well as its expression in the cartilage from fetus to adulthood. The expression of 11ß-HSD2, aggrecan and Col2a1 were all decreased by corticosterone in the fetal chondrocytes, while overexpression of 11ß-HSD2 could partially alleviate the decrease of matrix synthesis induced by corticosterone in vitro. Furthermore, the glucocorticoid receptor (GR) activated by glucocorticoids directly bonded to the promoter region of 11ß-HSD2 to inhibit its expression. Meanwhile, the activated GR reduced the H3K9ac and H3K27ac levels of 11ß-HSD2 by recruiting HDAC4 and promoting GR-HDAC4 protein interaction to inhibit the 11ß-HSD2 expression. Moreover, caffeine could reduce the expression of 11ß-HSD2 by inhibiting the cAMP/PKA signaling pathway but without reducing the H3K9ac and H3K27ac levels of 11ß-HSD2, thereby synergistically enhancing the corticosterone effect. In conclusion, the persistently reduced H3K9ac and H3K27ac levels of 11ß-HSD2 from fetus to adulthood mediated the inhibition of cartilage matrix synthesis and the increased susceptibility to osteoarthritis. This epigenetic programming change in utero was induced by glucocorticoids with synergistic effect of caffeine.

Exploring sex differences in fetal programming for childhood emotional disorders.

In examining maternal depression, placental 11ß-HSD2 mRNA expression and offspring cortisol regulation as a potential fetal programming pathway in relation to later child emotional disorders, it has become clear that sex differences may be important to consider. This study reports on data obtained from 209 participants in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS) recruited before 20 weeks of pregnancy. Maternal depressive disorders were diagnosed using the SCID-IV and maternal childhood trauma using the Childhood Trauma Questionnaire. Placental 11ß-HSD2 mRNA was measured using qRT-PCR. For assessment of stress-induced cortisol reactivity, salivary cortisol samples were taken at 12 months of age. At 4 years of age, measurement of Childhood Emotional Disorders (depression and anxiety) was based on maternal report using the Preschool Age Psychiatric Assessment (PAPA) and internalizing symptoms using the Child Behavior Checklist (CBCL). Maternal depression in pregnancy and postpartum, and infant cortisol reactivity, was associated with internalizing symptoms for females only. For female offspring only, increased 12-month cortisol reactivity was also associated with increased emotional disorders at 4 years of age; however, there was no association with placental 11ß-HSD2 mRNA expression. In females only, the combination of lower placental 11ß-HSD2 mRNA expression and higher cortisol reactivity at 12 months of age predicted increased internalising problems. These findings suggest there may be sex differences in prenatal predictors and pathways for early childhood depression and anxiety symptoms and disorder.

Effects of prenatal hypoxia on placental glucocorticoid barrier: Mechanistic insight from experiments in rats.

Prenatal hypoxia is the most common stress in mid-late gestation that usually arise from maternal, placental and/or fetal factors. As a multifunctional organ enabling optimal fetal growth, placenta must adapt to diverse environmental stressors. Excessive glucocorticoids exposure is known to have adverse effects on fetal growth. The fetus is shielded by a placental glucocorticoid barrier by 11ß-hydroxysteroid dehydrogenase 2 (11ß-HSD2). However, the effects and underlying mechanisms of intrauterine hypoxia on placental glucocorticoid barrier are largely unknown. This study was the first to determine the effects and its mechanisms. Pregnant rats were exposed to hypoxia (10.5% O2) from gestational day (GD)10-20. At GD20, expression of 11-ßHSD2 were determined in placenta, and corticosterone levels were measured in maternal and fetal plasma. Prenatal hypoxia disrupted the placental glucocorticoid barrier by suppressing 11-ßHSD2 expression. Meanwhile, the decreased 11-ßHSD2 was correlated with an increased DNA methylation within its gene promoter. Together, these results indicated that prenatal hypoxia impair placental glucocorticoid barrier, was strongly associated with reprogrammed 11-ßHSD2 expression via a DNA methylation-mediated epigenetic mechanism.

Selenium attenuates the cadmium-induced placenta glucocorticoid barrier damage by up-regulating the expression of specificity protein 1.

Cadmium (Cd) is an environmental pollutant and pregnant women are especially susceptible to the effects of exposure to Cd. Our previous study found Cd can be accumulated in the placenta and causes fetal growth restriction (FGR) through damage the placental glucocorticoid barrier. Selenium (Se), as an essential micronutrient, can allivate Cd-induced toxicity. In this study, we aim to explore the protective mechanism of Se against Cd-induced the placental glucocorticoid barrier damage and FGR. Pregnant Sprague Dawley (SD) rats were exposed to CdCl2 (1 mg/kg/day) and Na2 SeO3 (0.1-0.2-0.3 mg/kg/day) by gavage from gestational day (GD) 0 to GD 19. The results showed that reduced fetal weight, increased corticosterone concentrations in the maternal and fetal serum, and impaired placental labyrinth layer blood vessel development, appeared in pregnant rats after Cd exposure and improved after treated with Se. In cell experiments, we confirmed that Se reduces Cd-induced apoptosis. Moreover, Se can abolish Cd-induced 11ß-HSD2 and specificity protein 1 (Sp1) decreasing in vivo and vitro. In human JEG-3 cells, the knockdown of Sp1 expression by small interfering RNA can suppressed the protective effect of Se on Cd-induced 11ß-HSD2 decreasing. In general, our results demonstrated that Se is resistant to Cd-induced FGR through upregulating the placenta barrier via activation of the transcription factor Sp1.

Glucocorticoid Production in Lymphoid Organs: Acute Effects of Lipopolysaccharide in Neonatal and Adult Mice.

Glucocorticoids (GCs) are critical modulators of the immune system. The hypothalamic-pituitary-adrenal (HPA) axis regulates circulating GC levels and is stimulated by endotoxins. Lymphoid organs also produce GCs; however, it is not known how lymphoid GC levels are regulated in response to endotoxins. We assessed whether an acute challenge of lipopolysaccharide (LPS) increases lymphoid levels of progesterone and GCs, and expression of steroidogenic enzymes and key HPA axis components (eg, corticotropin-releasing hormone [CRH], adrenocorticotropic hormone [ACTH]). We administered LPS (50 µg/kg intraperitoneally) or vehicle control to male and female C57BL/6J neonatal (postnatal day [PND] 5) and adult (PND90) mice and collected blood, bone marrow, thymus, and spleen 4 hours later. We measured progesterone, 11-deoxycorticosterone, corticosterone, and 11-dehydrocorticosterone via liquid chromatography-tandem mass spectrometry. We measured gene expression of key steroidogenic enzymes (Cyp11b1, Hsd11b1, and Hsd11b2) and HPA axis components (Crh, Crhr1, Pomc, and Mc2r) via quantitative polymerase chain reaction. At PND5, LPS induced greater increases in steroid levels in lymphoid organs than in blood. In contrast, at PND90, LPS induced greater increases in steroid levels in blood than in lymphoid organs. Steroidogenic enzyme transcripts were present in all lymphoid organs, and LPS altered steroidogenic enzyme expression predominantly in the spleen. Lastly, we detected transcripts of key HPA axis components in all lymphoid organs, and there was an effect of LPS in the spleen. Taken together, these data suggest that LPS regulates GC production by lymphoid organs, similar to its effects on the adrenal glands, and the effects of LPS might be mediated by local expression of CRH and ACTH.

11ß-Hydroxysteroid dehydrogenase 2: A key mediator of high susceptibility to osteoporosis in offspring after prenatal dexamethasone exposure.

Epidemiological investigations have shown that individuals treated with dexamethasone during pregnancy have an increased risk of osteoporosis after birth. Our studies reported that peak bone mass was decreased in the prenatal dexamethasone exposure (PDE) offspring before chronic stress, while further decrease was observed after chronic stress. Simultaneously, increase of bone local active corticosterone was observed in the PDE offspring, while further increase was also observed after chronic stress. Moreover, the histone H3 lysine 9 acetylation (H3K9ac) level of 11-beta hydroxysteroid dehydrogenase 2 (11ß-HSD2) and its expression in bone tissue of PDE offspring rats remained lower than the control before and after birth. Injection of 11ß-HSD2 overexpression lentivirus into the bone marrow cavity could partially alleviate the accumulation of bone local active corticosterone and bone loss induced by PDE. In vitro, dexamethasone inhibited the expression of 11ß-HSD2 and aggravated the inhibitory effect of corticosterone on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Overexpression of 11ß-HSD2 partially alleviated the inhibitory effect of corticosterone. Moreover, dexamethasone promoted the nuclear translocation of glucocorticoid receptor (GR), which resulted in the stimulation of 11ß-HSD2 expression due to the binding of GR to the 11ß-HSD2 promoter region directly, as well as increasing H3K9ac level in the 11ß-HSD2 promoter region by recruiting histone deacetylase 11 (HDAC11). Our results indicated that low expression of 11ß-HSD2 in bone tissue is an important mediator for the high susceptibility to osteoporosis in PDE adult offspring.

Knockout of the hsd11b2 Gene Extends the Cortisol Stress Response in Both Zebrafish Larvae and Adults.

The Hsd11b2 enzyme converts cortisol into its inactive form, cortisone and regulates cortisol levels, in particular in response to stress. Taking advantage of CRISPR/Cas9 technology, we generated a hsd11b2 zebrafish mutant line to evaluate the involvement of this gene in stress response regulation. The absence of a functional Hsd11b2 affects survival of zebrafish, although homozygous hsd11b2-/- mutants can reach adulthood. Reproductive capability of hsd11b2-/- homozygous adult males is almost completely abrogated, while that of females is reduced. Interestingly, basal cortisol levels and glucocorticoid-dependent transcriptional activities are not affected by the mutation. In agreement with basal cortisol results, we also demonstrated that basal response to light (LMR-L/D) or mechanical (VSRA) stimuli is not significantly different in wild-type (hsd11b2+/+) compared to mutant larvae. However, after exposure to an acute stressor, the cortisol temporal patterns of synthesis and release are prolonged in both 5 days post fertilization larvae and one-year-old adult hsd11b2-/- zebrafish compared to wild-type siblings, showing at the same time, at 5 dpf, a higher magnitude in the stress response at 10 min post stress. All in all, this new zebrafish model represents a good tool for studying response to different stressors and to identify mechanisms that are induced by cortisol during stress response.

Detection of Urinary Exosomal HSD11B2 mRNA Expression: A Useful Novel Tool for the Diagnostic Approach of Dysfunctional 11ß-HSD2-Related Hypertension.

Objective: Apparent mineralocorticoid excess (AME) is an autosomal recessive disorder caused by the 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2) enzyme deficiency, traditionally assessed by measuring either the urinary cortisol metabolites ratio (tetrahydrocortisol+allotetrahydrocortisol/tetrahydrocortisone, THF+5αTHF/THE) or the urinary cortisol/cortisone (F/E) ratio. Exosomal mRNA is an emerging diagnostic tool due to its stability in body fluids and its biological regulatory function. It is unknown whether urinary exosomal HSD11B2 mRNA is related to steroid ratio or the HSD11B2 662 C>G genotype (corresponding to a 221 A>G substitution) in patients with AME and essential hypertension (EH). Aim of the Study: To detect and quantify HSD11B2 mRNA from urinary exosomes in samples from family members affected by AME and EH, and to evaluate the relationship between exosomal HSD11B2 mRNA, steroid ratio, 662C>G genotype, and hypertension. Methods: In this observational case-control study, urinary steroid ratios and biochemical parameters were measured. Urinary exosomes were extracted from urine and exosomal HSD11B2 mRNA was quantified by Droplet Digital PCR (ddPCR). B2M (ß-2 microglobulin) gene was selected as the reference housekeeping gene. Results: Among family members affected by AME, exosomal urinary HSD11B2 mRNA expression was strictly related to genotypes. The two homozygous mutant probands showed the highest HSD11B2 mRNA levels (median 169, range 118-220 copies/µl) that progressively decreased in 221 AG heterozygous with hypertension (108, range 92-124 copies/µl), 221 AG heterozygous normotensives (23.35, range 8-38.7 copies/µl), and wild-type 221 AA subjects (5.5, range 4.5-14 copies/µl). Heterozygous hypertensive subjects had more HSD11B2 mRNA than heterozygous normotensive subjects. The F/E urinary ratio correlated with HSD11B2 mRNA copy number (p < 0.05); HSD11B2 mRNA strongly decreased while THF+5αTHF/THE increased in the two probands after therapy. In the AME family, HSD11B2 copy number correlated with both F/E and THF+5αTHF/THE ratios, whereas in EH patients, a high F/E ratio reflected a reduced HSD11B2 mRNA expression. Conclusions: HSD11B2 mRNA is detectable and quantifiable in urinary exosomes; its expression varies according to the 662 C>G genotype with the highest levels in homozygous mutant subjects. The HSD11B2 mRNA overexpression in AME could be due to a compensatory mechanism of the enzyme impairment. Exosomal mRNA is a useful tool to investigate HSD11B2 dysregulation in hypertension.