Human Adrenocortical H295R Cells Research Articles

SAT269 Orexin Activates Adrenocortical Steroidogenesis With Upregulation Of BMP Signaling By Human H295R Cells

Abstract Disclosure: Y. Soejima: None. N. Iwata: None. R. Nishioka: None. M. Honda: None. Y. Nakano: None. K. Yamamoto: None. A. Suyama: None. F. Otsuka: None. Orexins are neuropeptides that express primarily in the hypothalamus and are composed of two isoforms, orexin A and orexin B. Orexin A binds to orexin receptor type 1 (OX1R) and type 2 (OX2R), while orexin B binds selectively to OX2R. Orexin has been reported to have important roles in various systems including sleep-wake regulation and feeding behavior in the central nervous system, whereas its receptors are also expressed in peripheral tissues including the endocrine system. The expression of orexin receptors and the effects of orexins on adrenocortical steroidogenesis have been shown in experiments using adrenocortical cells. Bone morphogenetic proteins (BMPs), which are members of the transforming growth factor (TGF)-β superfamily, also play functional roles in various endocrine tissues. In our previous experiments, we have revealed that BMP-6 enhances aldosterone production which is induced by angiotensin II through activation of mitogen-activated protein kinase (MAPK) signaling. We have also shown that peripheral clock genes have functional roles in modulating adrenocortical steroidogenesis by interacting with adrenocortical BMP system. However, the molecular mechanism of physiological effects of orexin and its interaction with BMP signaling remains unclear. In the present study, we investigated the effects of orexin on adrenal steroidogenesis using human adrenocortical H295R cells, by focusing on the interaction with adrenocortical BMP signaling. First, it was confirmed that both OX1R and OX2R were expressed in H295R cells. It was revealed that orexin A (10-300 nM) stimulation for 24 h directly increased mRNA levels of steroidogenic acute regulatory protein (StAR), cytochrome P450 family 11 subfamily B member 2 (CYP11B2) and cytochrome P450 family 17 subfamily A member 1 (CYP17A1) in a concentration-dependent manner. Orexin A further upregulated the expression of these steroidogenic enzymes in H295R cells co-treated with forskolin (FSK). Next, the interrelationship between orexin and BMP signaling was examined. Stimulation with BMP-6 readily activated Smad1/5/9 phosphorylation in H295R cells and the pretreatment with orexin A for 24 h enhanced the Smad1/5/9 phosphorylation induced by BMP-6. On the other hand, BMP-6 significantly suppressed the expression of OX1R but not that of OX2R. In our previous study, we have reported that BMP-6 upregulates the adrenocortical steroidogenesis via the IP3 and MAPK signaling in H295R cells, suggesting that orexin may have a pivotal role as a functional modulator of BMP-6. Collectively, it was revealed that orexin enhances adrenocortical steroidogenesis by regulating BMP signaling with a feedback system in human adrenocortical cells. Here, we will also discuss the relationship with BMP receptors and the effects on endogenous BMP expression. Presentation: Saturday, June 17, 2023

Interaction of Orexin and Bone Morphogenetic Proteins in Steroidogenesis by Human Adrenocortical Cells.

Orexins are neuropeptides that play important roles in sleep-wake regulation and food intake in the central nervous system, but their receptors are also expressed in peripheral tissues, including the endocrine system. In the present study, we investigated the functions of orexin in adrenal steroidogenesis using human adrenocortical H295R cells by focusing on its interaction with adrenocortical bone morphogenetic proteins (BMPs) that induce adrenocortical steroidogenesis. Treatment with orexin A increased the mRNA levels of steroidogenic enzymes including StAR, CYP11B2, CYP17, and HSD3B1, and these effects of orexin A were further enhanced in the presence of forskolin. Interestingly, orexin A treatment suppressed the BMP-receptor signaling detected by Smad1/5/9 phosphorylation and Id-1 expression through upregulation of inhibitory Smad7. Orexin A also suppressed endogenous BMP-6 expression but increased the expression of the type-II receptor of ActRII in H295R cells. Moreover, treatment with BMP-6 downregulated the mRNA level of OX1R, but not that of OX2R, expressed in H295R cells. In conclusion, the results indicate that both orexin and BMP-6 accelerate adrenocortical steroidogenesis in human adrenocortical cells; both pathways mutually inhibit each other, thereby leading to a fine-tuning of adrenocortical steroidogenesis.

Somatic mutations of CADM1 in aldosterone-producing adenomas and gap junction-dependent regulation of aldosterone production

Aldosterone-producing adenomas (APAs) are the commonest curable cause of hypertension. Most have gain-of-function somatic mutations of ion channels or transporters. Herein we report the discovery, replication and phenotype of mutations in the neuronal cell adhesion gene CADM1. Independent whole exome sequencing of 40 and 81 APAs found intramembranous p.Val380Asp or p.Gly379Asp variants in two patients whose hypertension and periodic primary aldosteronism were cured by adrenalectomy. Replication identified two more APAs with each variant (total, n = 6). The most upregulated gene (10- to 25-fold) in human adrenocortical H295R cells transduced with the mutations (compared to wildtype) was CYP11B2 (aldosterone synthase), and biological rhythms were the most differentially expressed process. CADM1 knockdown or mutation inhibited gap junction (GJ)-permeable dye transfer. GJ blockade by Gap27 increased CYP11B2 similarly to CADM1 mutation. Human adrenal zona glomerulosa (ZG) expression of GJA1 (the main GJ protein) was patchy, and annular GJs (sequelae of GJ communication) were less prominent in CYP11B2-positive micronodules than adjacent ZG. Somatic mutations of CADM1 cause reversible hypertension and reveal a role for GJ communication in suppressing physiological aldosterone production.

Extended steroid profiling in H295R cells provides deeper insight into chemical-induced disturbances of steroidogenesis: Exemplified by prochloraz and anabolic steroids

Human adrenocortical H295R cells have been validated by the OECD Test Guideline 456 to detect chemicals disrupting testosterone and 17β-estradiol (estradiol) biosynthesis. This study evaluated a novel approach to detect disturbances of steroidogenesis in H295R cells, exemplified by prochloraz and five anabolic steroids. Steroid profiles were assessed by an untargeted LC-MS-based method, providing a relative quantification of 57 steroids annotated according to their accurate masses and retention times. Such a panel of steroids included several mineralocorticoids, glucocorticoids, progestins and adrenal androgens. The coverage of a high number of metabolites in this extended steroid profiling facilitated grouping of chemicals with similar effects and detecting subtler differences between chemicals. It allowed, for example, distinguishing between the effects of turinabol and oxymetholone, supposed to act similarly in a previous characterization including only nine adrenal steroids. Furthermore, the results revealed that product/substrate ratios can provide superior information on altered enzyme activities compared to individual metabolite levels. For example, the 17α-hydroxypregnenolone/pregnenolone ratio was found to be a more sensitive marker for detecting 17α-hydroxylase inhibition by prochloraz than the corresponding individual steroids. These results illustrate that chemical grouping and calculation of product/substrate ratios can provide valuable information on mode-of-action and help prioritizing further experimental work.

S-13-3: AN APPROACH TO IDENTIFY THE UNDETERMINED ADIPOCYTE-DERIVED FACTOR(S) THAT STIMULATE ALDOSTERONE SYNTHASE GENE (CYP11B2) EXPRESSION

Objectives: Hypertension is a frequently observed complication among obese patients. Recently, undetermined adipocyte-derived factor(s) have been recognized as one of the causes of the obesity-related hypertension independent of angiotensin (A) II. In this study, we aim to identify the undetermined adipocyte-derived factor(s) that stimulate aldosterone synthase gene (CYP11B2) expression aldosterone secretion that may induce hypertension. Methods: We first differentiated mouse fibroblast 3T3-L1 cells into adipocytes and collected their supernatants. The supernatants were incubated with human adrenocortical carcinoma H295R cells, and their CYP11B2 mRNA expression was measured by quantitative PCR with reverse transcription (qRT-PCR). Thereafter, the supernatants were fractionated by ammonium sulfate precipitation to purify adipocyte-derived factor(s) that stimulate CYP11B2 expression. The precipitates were collected in 30%, 60% and 90% saturated concentration of ammonium sulfate. Each of precipitates was concentrated using 100 kDa ultrafiltration membrane and incubated with H295R cells. CYP11B2 mRNA expression in H295R cells was measured by qRT-PCR. Then, we purified the precipitation of the supernatants that obtained in 60% ammonium sulfate by anion-exchange chromatography. Each of the fractions was incubated with human adrenocortical carcinoma H295R cells, and their CYP11B2 mRNA expression was measured by qRT-PCR. Results: The supernatants obtained from 3T3-L1 adipocytes were demonstrated to stimulate CYP11B2 expression. Fractionation of the supernatants by ammonium sulfate precipitation demonstrated that the ability to stimulate CYP11B2 expression was detected in fractions precipitated in 60% saturated concentration. Fractionation of the supernatants by anion-exchange chromatography demonstrated that the ability to stimulate CYP11B2 expression was detected in two specific fractions. Specific fractions were analyzed by mass spectrometry, resulting in the identification of 39 specific proteins. We are now investigating that the relationship between CYP11B2 gene expression and 39 proteins.

PS-B04-9: ELUCIDATING EFFECT OF INHIBITING ALDOSTERONE SYNTHESIS ON HUMAN ADRENOCORTICAL CELLS

Introduction: Modern human diet is high in salt. High salt stimulates decrease of aldosterone by down-regulation of aldosterone synthase (encoded by the gene CYP11B2) in the zona glomerulosa (ZG). Aldosterone regulates blood pressure and volume by regulating salt secretion. Interestingly, adult human adrenal ZG is sparse and confined to discrete islets of cells unlike rodent adrenal where the zone encompasses the whole periphery of the adrenal. We therefore hypothesize that ZG cell function change from synthesis to apoptosis/migration mode when aldosterone is not required due to the high salt diet. Objective: Herein, we intend to characterise human adrenocortical cells silenced for CYP11B2. Methods: We transfected HAC15, a subclone of the H295R human adrenocortical cancer cell line with scrambled siRNA (siScrambled) or siRNA targeting CYP11B2 (siCYP11B2) using the Neon Transfection System. 48-h post-transfection, cell apoptosis rate was assessed using the Pacific Blue Annexin V/SYTOX AADvanced apoptosis kit. The supernatants and cells were harvested for aldosterone and cortisol measurements, and RNA isolation. A representative sample of siCYP11B2 and siScrambled from each independent experiment was selected for RNA-Sequencing (RNAseq). The EZMTT Proliferation Assay was performed on equally seeded HAC15 cells, 72-h post-transfection with either siScrambled or siCYP11B2 using the Lipofectamin 3000 Transfection reagent. Experiments were repeated 3 times independently in triplicates. Results: siCYP11B2 transfection limited the production of aldosterone by 69.8% (p = 0.001) and down-regulated the expression of CYP11B2 by 83.0% (p = 0.001). We confirmed that the silencing was specific to CYP11B2 despite the gene being highly homologous to CYP11B1 as there were no significant change on cortisol production and CYP11B1 mRNA expression. RNAseq analysis found 3 genes, CYP11B2, HNRNPA1, and UHMK1, consistently down-regulated in siCYP11B2 by 32%, 65% and 67% respectively. The most enriched pathways among the differentially expressed genes (DEG) were mitophagy and autophagy. No difference in cell apoptosis was seen in siCYP11B2 cells. Instead, an increase in cell proliferation was detected with the EZMTT assay. Conclusion: Our findings suggest that silencing of CYP11B2 does not affect apoptosis but does affect cell proliferation. Interestingly, the mitophagy and autophagy pathways were enriched in the DEGs of siCYP11B2 cells.

OR04-4 Loss of KDM1A in Bilateral Macronodular Adrenal Hyperplasia With GIP-Dependent Cushing's Syndrome and in Acromegaly With Paradoxical GH Response to Oral Glucose

Abstract Context Primary bilateral macronodular adrenal hyperplasia (PBMAH) with glucose-dependent insulinotropic polypeptide (GIP)-dependent Cushing's syndrome is caused by ectopic expression of GIP receptor (GIPR) in the adrenal lesions. Such ectopic expression of GIPR was also reported in other endocrine neoplasm, notably in somatotroph pituitary adenomas from acromegalic patients with paradoxical increase of GH after oral glucose load, suggesting a common molecular pathogenesis. We aimed to identify the driver event responsible for GIP-dependent PBMAH with Cushing's syndrome and ectopic GIPR expression in somatotropinomas. Methods We conducted an international, multicenter, cohort study. We collected blood and adrenal samples from patients who had undergone unilateral or bilateral adrenalectomy for GIP-dependent PBMAH with Cushing's syndrome. Adrenal samples from patients with PBMAH and Cushing's syndrome without food-dependent cortisol production were used as controls. We further collected somatotropinoma specimens from acromegaly patients followed at two expert endocrine centers in France. Results 17 patients with familial or sporadic GIP-dependent PBMAH with Cushing's syndrome were studied. We identified germline heterozygous mutations in the lysine demethylase 1A (KDM1A) gene in all 17 patients. We further identified a recurrent deletion of the short arm of chromosome 1 harboring the KDM1A locus in the adrenal lesions of affected patients. None of the 25 patients in the control group had KDM1A germline or somatic alterations. Concomitant genetic inactivation of both KDM1A alleles resulted in loss of KDM1A expression in the adrenal lesions. RNA-sequencing revealed the global impact of KDM1A loss in adrenal tissue on gene transcription and identified differentially regulated genes including those encoding for GIPR and other G-Protein-Coupled Receptors that may be involved in adrenal tumorigenesis and regulation of steroidogenesis. In vitro pharmacologic inhibition, silencing and knock-out by CRISPR-Cas9 genome editing of KDM1A led to an increase in GIPR transcripts and protein in human adrenocortical H295R cells. Somatotropinoma samples from 78 patients with acromegaly were studied. 24% of these patients presented with a paradoxical rise of GH after oral glucose load and expressed ectopically GIP-receptor in their somatotropinoma. None of the somatotropinomas harbored KDM1A pathogenic variants, but those from patients with paradoxical GH response displayed a recurrent chromosome 1p loss. Discussion We identified germline inactivating KDM1A mutations and loss of heterozygosity as a genetic predisposition to GIP-dependent PBMAH with Cushing's syndrome following a tumor suppressor gene model of tumorigenesis. We currently perform genetic screening in first-degree relatives of patients with GIP-dependent PBMAH with Cushing's syndrome and clinical examination with biochemical testing in asymptomatic KDM1A variant carriers. We did not identify somatic KDM1A mutations in somatotropinomas expressing GIPR ectopically, however their recurrent 1p chromosome loss suggests that KDM1A haploinsufficiency may contribute to GIPR expression in those tumors. Presentation: Saturday, June 11, 2022 12:15 p.m. - 12:30 p.m.

PSUN14 Elucidating Effect of Modulating Aldosterone Synthesis on Cell Fate in Human Adrenal Cells

Abstract Introduction Aldosterone regulates sodium homeostasis thereby affecting blood volume and blood pressure. Physiologically, aldosterone is synthesized in the zona glomerulosa (ZG) by aldosterone synthase (CYP11B2) when there is a lack of salt. However, in the adult human adrenal ZG is sparse and confined to discrete islets (1). We hypothesize that the high salt in modern diets change ZG cell function from synthesis to apoptosis/migration mode when aldosterone is not required. This hypothesis is based on: [i] CYP11B2−/− mice, where ZG cells migrate and apoptose (2); [ii] the disappearance from most of human ZG of CYP11B2, which became apparent with selective antisera (3); [iii] apoptosis in monkeys following aldosterone synthase inhibition (4). Herein we aim to test our hypothesis by silencing CYP11B2 in human adrenal cells. Methods The HAC15, a subclone of the H295R human adrenocortical cancer cell line, was transfected with scrambled siRNA (siScrambled) or siRNA targeting CYP11B2 (siCYP11B2) using the Neon™ Transfection System (Thermofisher Scientific, USA). An apoptosis assay 48-h post-transfection was performed using the Pacific Blue™ Annexin V/SYTOX™ AADvanced™ apoptosis kit on the BD FACSVerseTM system (BD Biosciences, USA). The supernatants and cells were harvested for aldosterone and cortisol, and RNA isolation. Experiments were repeated 3 times independently in triplicates. RNA-Sequencing (RNAseq) of siCYP11B2 and siScrambled was performed on a representative sample from each independent experiment (BGI Genomics, China). Results Transfected HAC15 cells with siCYP11B2 showed reduction of aldosterone production by 69.8% (p=0.001) and suppression of CYP11B2 mRNA by 8 folds (p=0.001) compared to control, with no significant change on cortisol production and CYP11B1 mRNA expression. This confirmed that the silencing was specific to CYP11B2 despite the gene being highly homologous to CYP11B1. In all 3 independent experiments, 3 genes were significantly downregulated; CYP11B2, HNRNPA1, and UHMK1 expression in siCYP11B2 cells were 32%, 65% and 67% of matched control siScramble cells. Result of KEGG pathway from each independent experiment showed the most enriched pathways among the differentially expressed genes (DEG) were mitophagy and autophagy. However, analysis of flow cytometric apoptosis assay showed silencing of CYP11B2 did not induce cell apoptosis. Conclusion Our finding showed that silencing of CYP11B2 can affect mitophagy and autophagy but does not affect cell apoptosis in the HAC15 human adrenocortical cancer cell line. Further investigation on cell proliferation and in non-cancerous adrenal cells may be needed to identify the effect of modulating aldosterone synthesis on ZG cell fate. Reference (1) Vinson G., Front Neurosci 2016; 10: 238. (2) Lee G, et al., Endocrinology 2005; 146: 2650–2656. (3) Gomez-Sanchez CE, et al., Mol Cell Endocrinol 2014; 383: 111–117. (4) Bogman K, et al., Hypertension. 2017; 69(1): 189–196. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Di-n-Butyl Phthalate and Its Monoester Metabolite Impairs Steroid Hormone Biosynthesis in Human Cells: Mechanistic In Vitro Studies.

The widespread environmental contaminant di-n-butyl phthalate (DBP) has been linked with reduced testosterone levels and adverse reproductive health outcomes in men. However, the underlying mechanisms of these anti-androgenic effects and the potential effects on other classes of steroid hormones remain to be elucidated. Here, we conducted mechanistic studies in human adrenocortical H295R cells exposed to 1–500 µM of DBP or its metabolite, mono-n-butyl phthalate (MBP), for 48 h. Quantification of steroid hormones in the cell medium by liquid chromatography-mass spectrometry revealed that both phthalates significantly decreased testosterone, androstenedione, corticosterone, and progesterone levels, in particular after dibutyryl-cyclic-AMP stimulation of steroidogenesis. Western blot analysis of key steroidogenic proteins showed that DBP induced a dose-dependent decrease of CYP11A1 and HSD3β2 levels, while MBP only significantly decreased CYP17A1 levels, indicating that the compounds affect early steps of the steroidogenesis differently. Both DBP and MBP exposure also lead to a dose-related decrease in HSD17β3, the enzyme which catalyzes the final step in the testosterone biosynthesis pathway, although these effects were not statistically significant. Interestingly, DBP increased the cortisol concentration, which may be due to the non-significant CYP11B1 increase in DBP-exposed cells. In contrast, MBP decreased cortisol concentration. Moreover, the analysis of superoxide generation and quantification of the protein oxidation marker nitrotyrosine demonstrated that DBP induced oxidative stress in H295R cells while MBP reduced protein nitrotyrosine levels. These findings confirm the anti-androgenic effects of DBP and MBP and reveal several differences in their toxicological mechanisms, with possible implications for future research on phthalate toxicity.

Novel regulation mechanism of adrenal cortisol and DHEA biosynthesis via the endogen ERAD inhibitor small VCP-interacting protein

Endoplasmic reticulum-associated degradation (ERAD) is a well-characterized mechanism of protein quality control by removal of misfolded or unfolded proteins. The tight regulation of ERAD is critical for protein homeostasis as well as lipid metabolism. Although the mechanism is complex, all ERAD branches converge on p97/VCP, a key protein in the retrotranslocation step. The multifunctionality of p97/VCP relies on its multiple binding partners, one of which is the endogenous ERAD inhibitor, SVIP (small VCP-interacting protein). As SVIP is a promising target for the regulation of ERAD, we aimed to assess its novel physiological roles. We revealed that SVIP is highly expressed in the rat adrenal gland, especially in the cortex region, at a consistently high level during postnatal development, unlike the gradual increase in expression seen in developing nerves. Steroidogenic stimulators caused a decrease in SVIP mRNA expression and increase in SVIP protein degradation in human adrenocortical H295R cells. Interestingly, silencing of SVIP diminished cortisol secretion along with downregulation of steroidogenic enzymes and proteins involved in cholesterol uptake and cholesterol biosynthesis. A certain degree of SVIP overexpression mainly increased the biosynthesis of cortisol as well as DHEA by enhancing the expression of key steroidogenic proteins, whereas exaggerated overexpression led to apoptosis, phosphorylation of eIF2α, and diminished adrenal steroid hormone biosynthesis. In conclusion, SVIP is a novel regulator of adrenal cortisol and DHEA biosynthesis, suggesting that alterations in SVIP expression levels may be involved in the deregulation of steroidogenic stimulator signaling and abnormal adrenal hormone secretion.

Loss of KDM1A in GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome: a multicentre, retrospective, cohort study

GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome is caused by aberrant expression of the GIP receptor in adrenal lesions. The bilateral nature of this disease suggests germline genetic predisposition. We aimed to identify the genetic driver event responsible for GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome. We conducted a multicentre, retrospective, cohort study at endocrine hospitals and university hospitals in France, Canada, Italy, Greece, Belgium, and the Netherlands. We collected blood and adrenal samples from patients who had undergone unilateral or bilateral adrenalectomy for GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome. Adrenal samples from patients with primary bilateral macronodular adrenal hyperplasia who had undergone an adrenalectomy for overt or mild Cushing's syndrome without evidence of food-dependent cortisol production and those with GIP-dependent unilateral adrenocortical adenomas were used as control groups. We performed whole genome, whole exome, and targeted next generation sequencing, and copy number analyses of blood and adrenal DNA from patients with familial or sporadic disease. We performed RNA sequencing on adrenal samples and functional analyses of the identified genetic defect in the human adrenocortical cell line H295R. 17 patients with GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome were studied. The median age of patients was 43·3 (95% CI 38·8-47·8) years and most patients (15 [88%]) were women. We identified germline heterozygous pathogenic or most likely pathogenic variants in the KDM1A gene in all 17 patients. We also identified a recurrent deletion in the short p arm of chromosome 1 harboring the KDM1A locus in adrenal lesions of these patients. None of the 29 patients in the control groups had KDM1A germline or somatic alterations. Concomitant genetic inactivation of both KDM1A alleles resulted in loss of KDM1A expression in adrenal lesions. Global gene expression analysis showed GIP receptor upregulation with a log2 fold change of 7·99 (95% CI 7·34-8·66; p=4·4 × 10-125), and differential regulation of several other G protein-coupled receptors in GIP-dependent primary bilateral macronodular hyperplasia samples compared with control samples. In vitro pharmacological inhibition and inactivation of KDM1A by CRISPR-Cas9 genome editing resulted in an increase of GIP receptor transcripts and protein in human adrenocortical H295R cells. We propose that GIP-dependent primary bilateral macronodular adrenal hyperplasia with Cushing's syndrome results from a two-hit inactivation of KDM1A, consistent with the tumour suppressor gene model of tumorigenesis. Genetic testing and counselling should be offered to these patients and their relatives. Agence Nationale de la Recherche, Fondation du Grand défi Pierre Lavoie, and the French National Cancer Institute.

Identification and Analysis of a Novel NR0B1 Mutation in Late-Onset Adrenal Hypoplasia Congenita and Hypogonadism

ObjectiveX-linked adrenal hypoplasia congenita (AHC) is a rare disorder characterized by primary adrenal insufficiency and hypogonadotropic hypogonadism (HHG) caused by mutations of the NR0B1/DAX1 gene. We aimed to search for the presence of any NR0B1/DAX1 gene mutations in a referred patient and to further characterize the phenotypes of the identified mutation.Case PresentationHerein, we report a Japanese patient with a novel missense mutation of the NR0B1/DAX1 gene resulting in adult-onset AHC and HHG. The patient was referred with diffuse skin pigmentation at 28 years of age, presented partial adrenal insufficiency and had undiagnosed incomplete HHG. Urological examination revealed severe oligospermia and testicular microlithiasis.ResultsThe NR0B1/DAX1 gene mutation was identified by exome sequencing as a novel missense mutation (c.884A>T, p.Leu295His). We conducted in silico modeling of this mutant NR0B1/DAX1 protein (p.Leu295His) which affected the conserved hydrophobic core of the putative ligand-binding domain (LBD). In addition, functional analysis revealed that this mutant showed a decreased ability as a transcriptional repressor to suppress target genes, such as STAR and LHB. Furthermore, this mutant showed functionally impaired repression of steroidogenesis in human adrenocortical H295R cells.ConclusionsWe identified a novel missense mutation of the NR0B1/DAX1 gene in a patient suffering from late-onset AHC and HHG, who presented with oligospermia and testicular microlithiasis. This mutant NR0B1/DAX1 protein was found to have reduced repressor activity, according to in vitro studies, clinically consistent with the patient’s phenotypic features.

Involvement of clock gene expression, bone morphogenetic protein and activin in adrenocortical steroidogenesis by human H295R cells.

Functional interactions between the levels of clock gene expression and adrenal steroidogenesis were studied in human adrenocortical H295R cells. Fluctuations of Bmal1, Clock, Per2 and Cry1 mRNA levels were found in H295R cells treated with forskolin (FSK) in a serum-free condition. The changes of clock gene expression levels were diverged, with Clock mRNA level being significantly higher than Cry1 and Per2 mRNA levels after 12-h stimulation with FSK. After FSK induction, mRNA levels of StAR and CYP11B2 were highest at 12 hours and CYP17 mRNA level reached a peak at 6 hours, but HSD3B1 mRNA level was transiently decreased at 3 hours. The expression levels of Clock mRNA showed a significant positive correlation with StAR among the interrelationships between mRNA levels of key steroidogenic factors and clock genes. Knockdown of Clock gene by siRNA led to a significant reduction of FSK-induced expression of StAR and CYP17 after 12-h treatment with FSK. BMP-6 and activin, which modulate adrenal steroidogenesis, had inhibitory effects on Clock mRNA expression, whereas treatment with follistatin, a binding protein of activin, increased Clock mRNA levels in the presence of FSK, suggesting an endogenous function of activin in regulation of Clock mRNA expression. Collectively, the results indicated that changes of Clock mRNA expression, being upregulated by FSK and suppressed by BMP-6 and activin, were tightly linked to StAR expression by human adrenocortical cells.

Nicotine-induced adrenal beta-arrestin1 upregulation mediates tobacco-related hyperaldosteronism leading to cardiac dysfunction.

BACKGROUNDTobacco-related products, containing the highly addictive nicotine together with numerous other harmful toxicants and carcinogens, have been clearly associated with coronary artery disease, heart failure, stroke, and other heart diseases. Among the mechanisms by which nicotine contributes to heart disease is elevation of the renin-angiotensin-aldosterone system (RAAS) activity. Nicotine, and its major metabolite in humans cotinine, have been reported to induce RAAS activation, resulting in aldosterone elevation in smokers. Aldosterone has various direct and indirect adverse cardiac effects. It is produced by the adrenal cortex in response to angiotensin II (AngII) activating AngII type 1 receptors. RAAS activity increases in chronic smokers, causing raised aldosterone levels (nicotine exposure causes the same in rats). AngII receptors exert their cellular effects via either G proteins or the two βarrestins (βarrestin1 and-2).AIMSince adrenal ßarrestin1 is essential for adrenal aldosterone production and nicotine/cotinine elevate circulating aldosterone levels in humans, we hypothesized that nicotine activates adrenal ßarrestin1, which contributes to RAAS activation and heart disease development.METHODSWe studied human adrenocortical zona glomerulosa H295R cells and found that nicotine and cotinine upregulate βarrestin1 mRNA and protein levels, thereby enhancing AngII-dependent aldosterone synthesis and secretion.RESULTSIn contrast, siRNA-mediated βarrestin1 knockdown reversed the effects of nicotine on AngII-induced aldosterone production in H295R cells. Importantly, nicotine promotes hyperaldosteronism via adrenal βarrestin1, thereby precipitating cardiac dysfunction, also in vivo, since nicotine-exposed experimental rats with adrenal-specific βarrestin1 knockdown display lower circulating aldosterone levels and better cardiac function than nicotine-exposed control animals with normal adrenal βarrestin1 expression.CONCLUSIONAdrenal βarrestin1 upregulation is one of the mechanisms by which tobacco compounds, like nicotine, promote cardio-toxic hyperaldosteronism in vitro and in vivo. Thus, adrenal βarrestin1 represents a novel therapeutic target for tobacco-related heart disease prevention or mitigation.

SUN-220 High Salt Intake May Paradoxically Drive Autonomous Aldosterone Production

Many modifiable factors contribute to the high prevalence rates of hypertension, among them is the consumption of too much salt (sodium). Another curable cause of hypertension is the excess of the hormone aldosterone. Aldosterone is normally produced by the zona glomerulosa (ZG) of the adrenal glands in response to a lack of salt and conversely suppressed by salt excess. We hypothesize that [i] suppression of aldosterone production induces apoptosis of ZG cells, as occurs following genetic deletion1; [ii] this sets up a maladaptive response to chronic salt overload by conferring a survival advantage to cells in which mutations drive autonomous aldosterone production. To address [i], we measured apoptosis of cells in which aldosterone synthesis was inhibited; to address [ii] we undertook a cross-sectional clinical study of aldosterone and sodium excretion, hypothesising that aldosterone excretion will be highest in the outside quartiles of sodium excretion. Aldosterone was inhibited by modification, in human adrenocortical H295R cells, of either CADM1 expression (mutated in aldosterone-producing adenomas2) or intracellular calcium concentration3. Apoptosis was measured by flow cytometric analysis of annexin V conjugates. 24-hour urinary aldosterone excretion (24h-Ualdo) was correlated with 24-hour urinary sodium (24h-Usodium) in 24h-urine samples collected for a Malaysian population-based salt intake study (MyCoSS). The prevalence of autonomous aldosterone production was estimated from the proportion of subjects with serum measurement whose “SUSSPUP” ratio (= serum sodium to urinary sodium)/(serum potassium2 to urinary potassium) was >5.34. Modification of CADM1 in human adrenocortical H295R cells decreased aldosterone production by half compared to vector control, and this was associated with a 3 to 5-fold increase of apoptotic cells (p<0.05; n>3). Pilot investigation of a Cav1.3 inhibitor decreased aldosterone production by 70%, and increased apoptosis by 7-fold (p<0.10; n=2). In 767 subjects, 24h-urine samples from the high urinary sodium quartile (>150mmol/d) had higher urinary aldosterone (4+0.18 ug/d) than other quartiles (p=0.00001). Overall, the estimated prevalence of autonomous aldossterone production using SUSSPUP ratio was 4.5% (8 of 179 subjects). In 63 subjects with 24h-Usodium>200 mmol/day, autonomous aldosterone secretion (conventionally >10µg/d) was found in 9.5%. Our results support the hypothesis that initial suppression of aldosterone production by salt excess may create a selective advantage for cells which autonomously produce aldosterone, and hence an inappropriate long-term increase in aldosterone production. 1Lee et al., Endocrinology. 2005;146:2650-6. 2Wu et al., 21st European Congress of Endocrinology. Vol. 63. BioScientifica, 2019. 3Xie et al., Sci Rep. 2016;6:24697. 4Willenberg et al., Eur J Clin Invest. 2009;39:43-50.

Glutaminases as a Novel Target for SDHB-Associated Pheochromocytomas/Paragangliomas.

Pheochromocytoma/paragangliomas (Pheo/PGL) are rare endocrine cancers with strong genetic background. Mutations in the SDHB subunit of succinate dehydrogenase (SDH) predispose patients to malignant disease with limited therapeutic options and poor prognosis. Using a host of cellular and molecular biology techniques in 2D and 3D cell culture formats we show that SDH inhibition had cell line specific biological and biochemical consequences. Based on our studies performed on PC12 (rat chromaffin cell line), Hela (human cervix epithelial cell line), and H295R (human adrenocortical cell line) cells, we demonstrated that chromaffin cells were not affected negatively by the inhibition of SDH either by siRNA directed against SDHB or treatment with SDH inhibitors (itaconate and atpenin A5). Cell viability and intracellular metabolite measurements pointed to the cell line specific consequences of SDH impairment and to the importance of glutamate metabolism in chromaffin cells. A significant increase in glutaminase-1 (GLS-1) expression after SDH impairment was observed in PC12 cells. GLS-1 inhibitor BPTES was capable of significantly decreasing proliferation of SDH impaired PC12 cells. Glutaminase-1 and SDHB expressions were tested in 35 Pheo/PGL tumor tissues. Expression of GLS1 was higher in the SDHB low expressed group compared to SDHB high expressed tumors. Our data suggest that the SDH-associated malignant potential of Pheo/PGL is strongly dependent on GLS-1 expression and glutaminases may be novel targets for therapy.

Profiling of anabolic androgenic steroids and selective androgen receptor modulators for interference with adrenal steroidogenesis

Anabolic-androgenic steroids (AAS) are testosterone derivatives developed for steroid-replacement and treatment of debilitating conditions. They are widely used by athletes in elite sports and bodybuilding due to their muscle-building and performance-enhancing properties. Excessive AAS use is associated with cardiovascular diseases, mood changes, endocrine and metabolic disorders; however, the underlying mechanisms remain unknown. Selective androgen receptor modulators (SARMs) aim to reduce adverse androgenic effects, while maximizing anabolic effects. This study assessed potential steroidogenic disturbances of 19 AAS and 3 SARMs in human adrenocortical carcinoma H295R cells, comparing basal and forskolin-activated states by mass spectrometry-based quantification of nine major adrenal steroids. Mesterolone, mestanolone and methenolone increased mineralocorticoid but decreased adrenal androgen production, indicating CYP17A1 dysfunction. Cell-free activity assays failed to detect direct CYP17A1 inhibition, supported by molecular modeling. The mRNA expression levels of 3β-HSD2, CYP17A1, CYP21A2, CYP11B1 and CYP11B2 were unaffected, suggesting indirect inhibition involving post-translational modification and/or impaired protein stability. Clostebol and oxymetholone decreased corticosteroid but increased dehydroepiandrosterone biosynthesis in H295R cells, suggesting CYP21A2 inhibition, sustained by molecular modeling. These AAS did not affect the expression of key steroidogenic genes. None of the SARMs tested interfered with steroidogenesis. The chosen approach allowed the grouping of AAS according to their steroidogenic-disrupting effects and provided initial mechanistic information. Mesterolone, mestanolone and methenolone potentially promote hypertension and cardiovascular diseases via excessive mineralocorticoid biosynthesis. Clostebol and oxymetholone might cause metabolic disturbances by suppressing corticosteroid production, resulting in adrenal hyperplasia. The non-steroidal SARMs exhibit an improved safety profile and represent a preferred therapeutic option.

The Effect of Soy Isoflavones on Steroid Metabolism.

Objective: This study is a post-hoc analysis of steroid hormones before and after administration of pharmacological doses of soy isoflavones in a large cohort of men and women from two independent studies. Isoflavones are reported to inhibit mineralo- and glucocorticoid hormone production as well as reproductive steroids in vivo and in vitro. We focused on cytochrome P450 17α-hydroxylase (CYP17A1) which catalyses the production of dehydroepiandrosterone (DHEA), in the androgen biosynthesis pathway to elucidate effects on sex steroids in vitro.Design and Setting: Effects of soy isoflavones on steroid levels in two studies comprising 400 patients were examined: 200 men (study 1; 3 months duration) and 200 postmenopausal women (study 2; 6 months duration), randomized to consume 15 g soy protein with 66 mg isoflavones (SPI) or 15 g soy protein alone without isoflavones (SP) daily. Effects of genistein and daidzein on steroid metabolism were determined in vitro, in HEK293 cells expressing CYP17A1 and in the human adrenocortical carcinoma H295R cell model.Results: SPI decreased serum dehydroepiandrosterone sulfate (DHEAS) levels in both men and women (P < 0.01), with decreased androstenedione (A4) (P < 0.01) in women not observed in men (P < 0.86). Cortisol, cortisone, 11-deoxycortisol, aldosterone, testosterone (T), or estradiol (E2) levels were unchanged. The dual hydroxylase and lyase activity of CYP17A1, which catalyses the biosynthesis of androgen precursors, and 3β-hydroxysteroid dehydrogenase (3βHSD2) were investigated in vitro. In transiently transfected HEK293 cells, only the lyase activity was inhibited by both genistein, 20% (P < 0.001) and daidzein, 58% (P < 0.0001). In forskolin-stimulated H295R cells DHEA production was decreased by daidzein (P < 0.05) and genistein, confirming inhibition of the lyase activity by the isoflavones.Conclusion: In Vivo clinical data suggested inhibition of CYP17A1 17,20 lyase within the adrenal in men and within the ovary and adrenal in females. This was confirmed in vitro with inhibition of the lyase activity by both genistein and daidzein. In addition, 3βHSD2 was inhibited perhaps accounting for decreased A4 levels observed in females. The decreased DHEAS and A4 levels together with the inhibition of the 17,20 lyase activity of CYP17A1, may impact production of androgens in clinical conditions associated with androgen excess.ISRCTN number: ISRCTN55827330ISRCTN number: ISRCTN 90604927

Bile acids increase steroidogenesis in cholemic mice and induce cortisol secretion in adrenocortical H295R cells via S1PR2, ERK and SF-1.

Background and AimsBile acids are now accepted as central signalling molecules for the regulation of glucose, amino acid and lipid metabolism. Adrenal gland cortex cells express the bile acid receptors farnesoid X receptor (FXR), the G protein‐coupled bile acid receptor (TGR5) and the sphingosine‐1‐phosphate receptor 2 (S1PR2). We aimed to determine the effects of cholestasis and more specifically of bile acids on cortisol production.Methods FXR and TGR5 knockout mice and controls were subjected to common bile duct ligation (CBDL) or chenodeoxycholic acid (CDCA) feeding to model cholestasis. Human adrenocortical H295R cells were challenged with bile acids for mechanistic studies.ResultsWe found that CBDL and CDCA feeding increased the levels of corticosterone, the rodent equivalent to human cortisol and mRNA and protein levels of steroidogenesis‐related enzymes in adrenals independent of FXR and TGR5. Taurine‐conjugated CDCA (TCDCA) significantly stimulated cortisol secretion, phosphorylation of extracellular signal‐regulated kinase (ERK) and expression of steroidogenesis‐related genes in human adrenocortical H295R cells. FXR and TGR5 agonists failed to induce cortisol secretion in H295R cells. S1PR2 inhibition significantly abolished TCDCA‐induced cortisol secretion, lowered phosphorylation of ERK and abrogated enhanced transcription of steroidogenesis‐related genes in H295R cells. Likewise, siRNA S1PR2 treatment reduced the phosphorylation of ERK and cortisol secretion. Steroidogenic factor‐1 (SF‐1) transactivation activity was increased upon TCDCA treatment suggesting that bile acid signalling is linked to SF‐1. Treatment with SF‐1 inverse agonist AC45594 also reduced TCDCA‐induced steroidogenesis.ConclusionsOur findings indicate that supraphysiological bile acid levels as observed in cholestasis stimulate steroidogenesis via an S1PR2‐ERK‐SF‐1 signalling pathway.

Effects of defined mixtures of POPs and endocrine disruptors on the steroid metabolome of the human H295R adrenocortical cell line

The presence of environmental pollutants in our ecosystem may impose harmful health effects to wildlife and humans. Several of these toxic chemicals have a potential to interfere with the endocrine system. The adrenal cortex has been identified as the main target organ affected by endocrine disrupting chemicals. The aim of this work was to assess exposure effects of defined and environmentally relevant mixtures of chlorinated, brominated and perfluorinated chemicals on steroidogenesis, using the H295R adrenocortical cell line model in combination with a newly developed liquid chromatography tandem mass spectrometry (LC-MS/MS) method. By using this approach, we could simultaneously analyze 19 of the steroids in the steroid biosynthesis pathway, revealing a deeper insight into possible disruption of steroidogenesis. Our results showed a noticeable down-regulation in steroid production when cells were exposed to the highest concentration of a mixture of brominated and fluorinated compounds (10,000-times human blood values). In contrast, up-regulation was observed with estrone under the same experimental condition, as well as with some other steroids when cells were exposed to a perfluorinated mixture (1000-times human blood values), and the mixture of chlorinated and fluorinated compounds. Interestingly, the low concentration of the perfluorinated mixture alone produced a significant, albeit small, down-regulation of pregnenolone, and the total mixture a similar effect on 17-hydroxypregnenolone. Other mixtures resulted in only slight deviations from the control. Indication of synergistic effects were noted when we used a statistical model to improve data interpretation. A potential for adverse outcomes of human exposures is indicated, pointing to the need for further investigation into these mixtures.