Endogenously released or exogenously administered glucocorticosteroids are relevant hormones for controlling inflammation. Only 11β-hydroxy glucocorticosteroids, but not 11-keto glucocorticosteroids, activate glucocorticoid receptors. Since we found that glomerular mesangial cells (GMC) express 11β-hydroxysteroid dehydrogenase 1 (11β-OHSD1), which interconverts 11-keto glucocorticosteroids into 11β-hydroxy glucocorticosteroids (cortisone/cortisol shuttle), we explored whether 11β-OHSD1 determines the antiinflammatory effect of glucocorticosteroids. GMC exposed to interleukin (IL)-1β or tumor necrosis factor α (TNF-α) release group II phospholipase A2 (PLA2), a key enzyme producing inflammatory mediators. 11β-hydroxy glucocorticosteroids inhibited cytokine-induced transcription and release of PLA2 through a glucocorticoid receptor–dependent mechanism. This inhibition was enhanced by inhibiting 11β-OHSD1. Interestingly, 11-keto glucocorticosteroids decreased cytokine-induced PLA2 release as well, a finding abrogated by inhibiting 11β-OHSD1. Stimulating GMC with IL-1β or TNF-α increased expression and reductase activity of 11β-OHSD1. Similarly, this IL-1β– and TNF-α–induced formation of active 11β-hydroxy glucocorticosteroids from inert 11-keto glucocorticosteroids by the 11β-OHSD1 was shown in the Kiki cell line that expresses the stably transfected bacterial β-galactosidase gene under the control of a glucocorticosteroids response element. Thus, we conclude that 11β-OHSD1 controls access of 11β-hydroxy glucocorticosteroids and 11-keto glucocorticosteroids to glucocorticoid receptors and thus determines the anti-inflammatory effect of glucocorticosteroids. IL-1β and TNF-α upregulate specifically the reductase activity of 11β-OHSD1 and counterbalance by that mechanism their own proinflammatory effect.

The aryl hydrocarbon receptor (AHR) binds many aromatic hydrocarbon compounds and mediates their carcinogenesis. We demonstrate that the endogenous AHR physically associates with the endogenous TRAP/DRIP/ARC/Mediator complex in a ligand-dependent manner. The Med220 subunit, which is known to interact with several nuclear hormone receptors through its LXXLL motifs, potentiates AHR-dependent reporter gene activity in an LXXLL-independent manner. Depletion of Med220 substantially reduces endogenous AHR-mediated transcription from the mouse cytochrome P4501A1 gene (CYP1A1). Both Med220 and CDK8 (another subunit of TRAP/DRIP/ARC/Mediator) are recruited to the CYP1A1 enhancer in a TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)-dependent fashion in vivo, and Med220 LXXLL motifs are not required. Med220 rapidly and persistently associates with the enhancer but not the promoter of the CYP1A1 gene after TCDD treatment with similar kinetics as AHR and the coactivators p300 and p/CIP. Our findings demonstrate a novel role for Med220 in AHR-regulated transcription that differs mechanistically from its role in transcriptional regulation by other previously studied transcription factors.

During pregnancy, trophoblasts grow to adapt the feto-maternal unit to fetal requirements. Aldosterone and cortisol levels increase, the latter being inactivated by a healthy placenta. By contrast, preeclamptic placental growth is reduced while aldosterone levels are low and placental cortisol tissue levels are high due to improper deactivation. Aldosterone acts as a growth factor in many tissues, whereas cortisol inhibits growth. We hypothesized that in preeclampsia low aldosterone and enhanced cortisol availability might mutually affect placental growth and function. Proliferation of cultured human trophoblasts was time- and dose-dependently increased with aldosterone (P < 0.04 to P < 0.0001) and inhibited by spironolactone and glucocorticoids (P < 0.01). Mineralo- and glucocorticoid receptor expression and activation upon agonist stimulation was verified by visualization of nuclear translocation of the receptors. Functional aldosterone deficiency simulated in pregnant mice by spironolactone treatment (15 μg/g body weight/day) led to a reduced fetal umbilical blood flow (P < 0.05). In rat (P < 0.05; R² = 0.2055) and human (X² = 3.85; P = 0.0249) pregnancy, placental size was positively related to plasma aldosterone. Autocrine production of these steroid hormones was excluded functionally and via the absence of specific enzymatic transcripts for CYP11B2 and CYP11B1. In conclusion, activation of mineralocorticoid receptors by maternal aldosterone appears to be required for trophoblast growth and a normal feto-placental function. Thus, low aldosterone levels and enhanced cortisol availability may be one explanation for the reduced placental size in preeclampsia and related disorders.

Cholesterol efflux from CHOP cells transfected with sterol 27-hydroxylase (CYP27A1) was compared with non-transfected and mock-transfected cells. Transfection caused expression of CYP27A1, formation of 27-hydroxycholesterol, and inhibition of cholesterol biosynthesis. Transfection enhanced cholesterol efflux to apolipoprotein A-I or human plasma by 2-3-fold but did not affect the efflux in the absence of acceptor. The analysis of released sterols revealed that 27-hydroxycholesterol represented only a small proportion of sterols, most of which was non-oxidized cholesterol. Time course and dose dependence studies showed that expression of CYP27A1 in CHOP cells mostly affected the efflux of the "fast" cholesterol pool, and relatively more cholesterol was released with low concentrations of an acceptor. Preincubation of non-transfected cells with exogenous 27-hydroxycholesterol (10(-9) and 10(-7) m) led to the stimulation of cholesterol efflux by 24-60%. Expression of CYP27A1 in CHOP cells did not affect ABCA1 expression and abundance of ABCA1 protein. Thus, introduction of CYP27A1 into cells stimulates cholesterol efflux and therefore may increase protection against atherosclerosis.

Aldosterone levels are markedly elevated during normal pregnancy but fall even though volume contracts when preeclampsia occurs. The level of aldosterone in either condition cannot be explained solely by the activity of the renin–angiotensin II system. In normal gestation, vascular endothelial growth factor (VEGF) is thought to maintain vascular health, but its role in adrenal hormone production is unknown. We hypothesized that the role of VEGF in the adrenal gland is to maintain vascular health and regulate aldosterone production. Here, we demonstrate that supernatant of endothelial cells grown in the presence of VEGF enhanced aldosterone synthase activity in human adrenocortical cells. VEGF either alone or combined with angiotensin II increased aldosterone production in adrenal cells. These data suggest that endothelial cell–dependent and independent activation of aldosterone is regulated by VEGF. In contrast to angiotensin II, VEGF did not upregulate the steroidogenic acute regulatory protein. Consistent with this observation, angiotensin II stimulated both aldosterone and cortisol synthesis from progesterone, whereas VEGF stimulated selectively aldosterone production. In rats, overexpression of soluble fms-like tyrosine kinase-1, an endogenous VEGF inhibitor, led to adrenocortical capillary rarefaction and fall in aldosterone concentrations that correlated inversely with soluble fms-like tyrosine kinase-1 levels. These findings may explain why aldosterone increases so markedly during normal gestation and why preeclampsia, a condition characterized by high soluble fms-like tyrosine kinase-1, is associated with inappropriately low aldosterone levels in spite of relatively lower plasma volumes.

Urinary steroid metabolomics by GC-MS is an established method in both clinical and research settings to describe steroidogenic disorders. However, population-based reference intervals for adults do not exist. We measured daytime and night time urinary excretion of 40 steroid metabolites by GC-MS in 1128 adult participants of European ancestry, aged 18 to 90 years, within a large population-based, multicentric, cross-sectional study. Age and sex-related patterns in adjacent daytime and night time urine collections over 24 hours were modelled for each steroid metabolite by multivariable linear mixed regression. We compared our results with those obtained through a systematic literature review on reference intervals of urinary steroid excretion. Flexible models were created for all urinary steroid metabolites thereby estimating sex- and age-related changes of the urinary steroid metabolome. Most urinary steroid metabolites showed an age-dependence with the exception of 6β-OH-cortisol, 18-OH-cortisol, and β-cortol. Reference intervals for all metabolites excreted during 24 hours were derived from the 2.5^th and 97.5^th percentile of modelled reference curves. The excretion rate per period of metabolites predominantly derived from the adrenals was mainly higher during the day than at night and the correlation between day and night time metabolite excretion was highly positive for most androgens and moderately positive for glucocorticoids. This study gives unprecedented new insights into sex- and age-specificity of the human adult steroid metabolome and provides further information on the day/night variation of urinary steroid hormone excretion. The population-based reference ranges for 40 GC-MS-measured metabolites will facilitate the interpretation of steroid profiles in clinical practice.