Adrenomedullin: new inhibitory regulator for cortisol synthesis and secretion.

Preterm birth is associated with immaturity of several crucial physiological functions notably those prevailing in the lung and kidney. Recently, a steroid secretion deficiency was identified in very preterm neonates, associated with a partial yet transient deficiency in 11ß-hydroxylase activity, sustaining cortisol synthesis. However, the P450c11ß enzyme is expressed in preterm adrenal glands, we hypothesized an inhibition of cortisol production by adrenomedullin (ADM), a peptide highly produced in neonates and whose effect on steroidogenesis remains poorly known. We studied the effects of ADM on three models: 104 cord-blood samples of the PREMALDO neonate cohort, genetically targeted mice overexpressing ADM, and two human adrenocortical cell lines (H295R and HAC15 cells). Mid-regional-proADM (MR-proADM) quantification in cord-blood samples showed strong negative correlation with gestational age (P = 0.0004), cortisol production (P < 0.0001), and 11ß-hydroxylase activity index (P < 0.0001). Mean MR-proADM was higher in very preterm than in term neonates (1.12 vs 0.60 nmol/L, P < 0.0001). ADM-overexpression mice revealed a lower 11ß-hydroxylase activity index (P < 0.05). Otherwise, aldosterone levels measured by LC-MS/MS were higher in ADM-overexpression mice (0.83 vs 0.46 ng/mL, P < 0.05). More importantly, the negative relationship between adrenal ADM expression and aldosterone production found in control was lacking in the ADM-overexpression mice. Finally, LC-MS/MS and gene expression studies on H295R and HAC15 cells revealed an ADM-induced inhibition of both cortisol secretion in cell supernatants and CYP11B1 expression. Collectively, our results converge toward an inhibitory effect of ADM on glucocorticoid synthesis in humans and should be considered to explain the steroid secretion deficiency observed at birth in premature newborns.

Urinary steroidomic profiles by LC-MS/MS to monitor classic 21-Hydroxylase deficiency.

21-hydroxylase deficiency, the most common enzyme defect associated with congenital adrenal hyperplasia (CAH) is characterized by an impairment of both aldosterone and cortisol biosynthesis. Close clinical and biological monitoring of Hydrocortisone (HC) and 9α-Fludrocortisone (FDR) replacement therapies is required to achieve an optimal treatment. As frequent and repeated reassessments of plasma steroids, 17-hydroxyprogesterone (17-OHP), androstenedione (Δ4-A) and testosterone (TESTO) is needed in childhood, urine steroid profiling could represent an interesting non-invasive alternative. We developed and validated a LC-MS/MS method for the measurement of 23-urinary mineralocorticoids, glucocorticoids and adrenal androgens. The usefulness of steroid profiling was investigated on single 08h00 am-collected spot urine for discriminating between 61 CAH patients and their age- and sex-matched controls. CAH patients were split into two groups according to their 08h00 am-plasma concentrations of 17-OHP: below (controlled patients, n = 26) and above 20 ng/mL (uncontrolled patients, n = 35). The lower limit of quantification and the wide analytical range allows to assay both free and total concentrations of the main urinary adreno-corticoids and their tetra-hydrometabolites. Extraction recoveries higher than 75% and intra-assay precision below 20% were found for most steroids. Urinary steroids upstream of the 21-hydroxylase defect were higher in uncontrolled CAH patients. Among CAH patients, plasma and urinary 17-OHP were closely correlated. As compared to controls, steroids downstream of the enzyme defect collapsed in CAH patients. This fall was more pronounced in controlled than in uncontrolled patients. Androgens (Δ4-A, TESTO and the sum etiocholanolone + androsterone) accumulated in uncontrolled CAH patients. A strong relationship was observed between plasma and urinary levels of androstenedione. Daily doses and urinary excretion of both FDR and HC were similar in both CAH groups. Urinary FDR was inversely related to the sodium-to-potassium ratio in urine. A partial least squares discriminant analysis model allowed to classify the patient's classes unaffected, controlled and un-controlled CAH patients based on urinary steroidomic profiles. Our LC-MS/MS method successfully established steroid profiling in urine and represents a useful and non-invasive tool for discriminating CAH patients according to treatment efficiency.

Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

Mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) are two closely related hormone-activated transcription factors that regulate major pathophysiologic functions. High homology between these receptors accounts for the crossbinding of their corresponding ligands, MR being activated by both aldosterone and cortisol and GR essentially activated by cortisol. Their coexpression and ability to bind similar DNA motifs highlight the need to investigate their respective contributions to overall corticosteroid signaling. Here, we decipher the transcriptional regulatory mechanisms that underlie selective effects of MRs and GRs on shared genomic targets in a human renal cellular model. Kinetic, serial, and sequential chromatin immunoprecipitation approaches were performed on the period circadian protein 1 ( PER1) target gene, providing evidence that both receptors dynamically and cyclically interact at the same target promoter in a specific and distinct transcriptional signature. During this process, both receptors regulate PER1 gene by binding as homo- or heterodimers to the same promoter region. Our results suggest a novel level of MR-GR target gene regulation, which should be considered for a better and integrated understanding of corticosteroid-related pathophysiology.-Le Billan, F., Amazit, L., Bleakley, K., Xue, Q.-Y., Pussard, E., Lhadj, C., Kolkhof, P., Viengchareun, S., Fagart, J., Lombès, M. Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

Comparative profiling of adrenal steroids in maternal and umbilical cord blood.

Fetal steroidome in late pregnancy receives multiple contributions from both maternal and fetal adrenals as well as from placenta. Depressed glucocorticoid levels have been reported in fetal blood at birth, yet studies on mineralocorticoid pathways are sparse. To investigate biosynthesis pathways at birth, adrenal steroids profiles were established in paired mothers and neonates. Forty-six paired healthy term newborns and their mothers from the Aldo cohort were assessed. Steroidomic profiles of mineralocorticoids, glucocorticoids and adrenal androgens were established from umbilical cord and maternal blood at birth using a highly sensitive and specific LC-MS/MS methodology. As compared to maternal blood, umbilical cord blood exhibited high levels of steroids precursors (progesterone and 11-deoxycorticosterone) contrasting with a collapse in corticosterone levels. Consecutively, 18-hydroxycorticosterone and aldosterone levels were also depressed in neonates. Similarly, umbilical cord blood levels of both 17-hydroxyprogesterone and 11-deoxycortisol were higher while cortisol levels sharply decreased. The product-to-substrate ratios evaluating the 11-hydroxylation step (corticosterone/11-deoxycorticosterone and cortisol/11-deoxycortisol) fell for both pathways. As expected, cortisone and 11-dehydrocorticosterone levels exceed those of cortisol and corticosterone in umbilical cord blood reflecting the strong placental 11-ß-hydroxysteroid-dehydrogenase type 2 (11ßHSD2) activity. Dehydroepiandrosterone-sulphate levels are higher in neonates, while both androstenedione and testosterone levels sharply fell. No significant difference in steroid levels could be observed according the gender except higher testosterone concentrations in umbilical cord of boys. Moreover, a strong and negative relationship between testosterone and progesterone levels was recorded in umbilical cord of boys. These adrenal steroidomic profiling demonstrate a deficit in mineralocorticoids (aldosterone, 18-hydroxycorticosterone and corticosterone) and glucocorticoids (cortisol) in term neonates, reflecting either a relative defect in 11-hydroxylase activity or more likely the strong placental 11-ß-HSD2 activity. Collectively, these findings should be taken into account for a better understanding of regulatory interactions between placenta and fetal adrenal.