CYP11B2 Expression Research Articles

Somatic Mutations of GNA11 and GNAQ in CTNNB1-Mutant Aldosterone-Producing Adenomas Increases Aldosterone and Aldosterone Synthase (CYP11B2)

Abstract Most aldosterone-producing adenomas (APA) have gain-of-function somatic mutations of ion channels or transporters. However, their frequency in aldosterone-producing cell-clusters of normal adrenals suggests the existence of co-driver mutations which influence the development or phenotype of APAs. Gain-of-function mutations in both CTNNB1 and GNA11 were found by whole exome sequencing in 3 of 41 APAs from a UK/Irish cohort. Targeted sequencing for exon 3 mutations of CTNNB1 and p.Gln209 mutations of either GNA11 or closely homologous GNAQ confirmed these and 7 further double mutant APAs in this discovery cohort. The presence of GNA11/Q p.Gln209 mutations in CTNNB1 mutant APAs were replicated in 2 cohorts from France (n=14) and Sweden (n=3). In total, 16 (59%) of the 27 CTNNB1 mutant APAs investigated had a mutation at p.Gln209 of GNA11 (n=11) or GNAQ (n=5). Interestingly, CTNNB1-mutant APAs were more commonly present in women (23/27), and of these, those with GNA11/Q mutations were all women except for a pubertal boy. To also note, 9 of 10 of the UK/Irish double mutant APAs in the discovery cohort presented in puberty, pregnancy, or menopause. Mutation of p.Gln209, or homologous p.Gln in GNAS, GNA12-14, impair hydrogen bonds between G-protein α and β subunits. Transfection of H295R cells, an immortalised adrenocortical cell line heterozygous for the p.Ser45Pro mutation of CTNNB1 but wild-type for GNA11-14/Q/S, by each of the GNA11/Q mutations increased aldosterone secretion and CYP11B2 expression (encoding aldosterone synthase) by 1.93-6.1-fold and 8.0-9.8-fold respectively, compared to vector or wild-type -transfected cells. In ZG, GNA11/Q mediate the aldosterone response to angiotensin II, via stimulation of intracellular Ca2+ release by inositol trisphosphate. In the mutant-transfected cells, the stimulatory effect of angiotensin II 10 nM was retained. In order to determine whether the p.Gln209 mutations stimulate aldosterone production even in the absence of CTNNB1 activation, the transfections of H295R cells were repeated after either 24-h treatment with the CTNNB1 inhibitor, ICG-001, or silencing of CTNNB1 using the ONTARGETplus SMARTpool SiRNAs (Dharmacon). Both interventions reduced the aldosterone production relative to vehicle/control-treated cells; however neither ICG-001 nor silencing of CTNNB1 blunted the fold-increase in aldosterone secretion seen in mutant-transfected cells compared to wild-type. In summary, we report the discovery of gain-of-function mutations of the G-protein, GNA11, or its close homologue, GNAQ, in multiple APAs which majority presented during periods of high LH/HCG. To date, the mutation is always residue p.Gln209, and associated with a gain-of-function mutation of CTNNB1. These GNA11/Q p.Gln209 mutations increase aldosterone and CYP11B2 production both in the presence and in the absence of CTNNB1 activation.

A Case of Adrenocortical Carcinoma With Severe Hypertension and Hypokalemia

Abstract Case: 70 years old woman was pointed out for hypertension at a medical checkup and visited a primary physician. Severe hypokalemia (2.4 mmol/L) was noted, and abdominal CT scan revealed a right 99 mm diameter adrenal tumor adjacent to a 80 mm diameter liver tumor. She was referred to our hospital for further management. Despite treatment with antihypertensive agents, including ARB, MRB, and CCB, her blood pressure remained around 170/90 mmHg. In the meantime, 120 meq of potassium chloride treatment was needed to keep her serum potassium levels around 3.5 mmol/L. Both her plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were high (6.4 ng/mL/h and 376 pg/mL), indicating renin-dependent hypertension. Since CT angiography revealed the right renal artery compressed downward by the adrenal tumor, renovascular hypertension was suspected. Moreover, both early morning plasma ACTH levels and serum cortisol levels were suppressed (8.5 pmol/L and 5.3 μg/dL), despite elevated urinary free cortisol levels (350 μg/day). Urinary steroid profile analysis detected various elevated precursor steroid metabolites, including deoxycorticosterone (DOC) and corticosterone. DOC levels were 5 folds more than the upper normal limit, suggesting one of the causes of her hypertension with hypokalemia, while elevated corticosterone levels were thought to be contributed to suppressing ACTH. After the right adrenalectomy and hepatic segmentectomy, both of her hypertension and hypokalemia rapidly improved with declining PRA and PAC levels to 0.2 ng/mL/h and < 0.7 pg/mL, respectively. Urinary DOC levels also fell into the normal range. From the pathological findings, she was diagnosed with adrenocortical carcinoma (ACC) infiltrating the liver (pT4N0M0, stage IV). The immunohistochemistry analysis showed disorganized expression of steroidogenic enzymes, including CYP11B1, CYP11B2, and 3β-HSD, supporting a variety production of steroid metabolites from the ACC. Although mitotane was initiated as a adjuvant chemotherapy, multiple metastasis was found at her lung, liver, and vertebrae, 6 months after the operation. Along with that, hypertension and hypokalemia recurred gradually with both of PRA and PAC elevation. However, CT angiography detected no apparent renovascular stenosis. We performed renin immunostaining of ACC specimen revealed partially positive, demonstrating renin production from this ACC. Conclusion: Although juxtaglomerular cell tumor is the most common renin-producing tumor, some cases of renin secreting ACC have been reported as a quite rare case. In the present case, renin secretion from ACC might be contributed to severe hypertension and hypokalemia, and both renal artery stenosis and DOC secretion induced by the ACC are considered to be a major cause.

Alteration in Aromatase and Estrogen Receptor Target Gene Expression in Human Benign Mammary Tissue After Bariatric Surgery

Abstract Background: Over 30% of US adults are obese (body mass index (BMI) of ≥ 30 kg/m2). Obesity is considered a significant and modifiable risk factor for ER+ postmenopausal breast cancer (BC). However, the effect on pre-menopausal breast cancer risk is less clear. Bariatric surgery is performed on obese patients who have a BMI of >35. It has been associated with reduced risk of BC, but the mechanisms behind this are unknown. Studies in obese patients have revealed multiple changes in the physiology of the microenvironment that contribute to BC development. The molecular changes in the stroma and epithelium from metabolic syndrome, excess inflammation, and ectopic hormone synthesis likely play key role in obesity related BC. Therefore, understanding how we can alter the risk posed will have an impact on decreasing the incidence of BC. We hypothesize that bariatric surgery will reduce the incidence of postmenopausal ER+ BC by reducing estradiol availability and ER activity. Methods: We recruited 30 women undergoing bariatric surgery, who underwent core needle biopsy at the time of surgery and after they had lost 25% of their excess body weight. Changes in hormone concentration by LCMS/MS in serum and breast tissue, protein expression in breast tissue by IHC and the altered gene expression in breast epithelium and stroma by RNA seq were measured. Results: When segregated by menopausal status, Androstenedione (p=0.02), Testosterone (p < 0.0001) and 27-hydroxycholesterol (p=0.017) showed significant reduction in the plasma post-surgery in premenopausal women. There were no significant differences in the hormone levels in the breast tissue and in postmenopausal women post-surgery. We observed that African Americans (AA) were half as likely to show a reduction in tissue concentration compared to Caucasian women. IHC was performed to examine protein expression of Ki67, leptin R, aromatase, CYP27A1, Stat3, adiponectin, CYP27B1 and ER in the breast core biopsy. Aromatase expression (p < 0.0001) was significantly reduced in both the epithelial and stromal compartments. In addition, Stat3 levels (p=0.044) were significantly reduced in the stroma. RNA -seq analysis revealed distinct differentially expressed genes pre and post-surgery. Specifically, genes associated with metabolic process, epithelial development, extracellular space, immune and inflammatory response pathways. Furthermore, known ER target genes TFF1, AGR2 expression were significantly decreased in Caucasian women, but not in AA women, post- surgery. Conclusions: Taken together, these data show that bariatric surgery decreased aromatase expression, some hormones in pre-menopausal women and reduced estrogen availability and ER activity. Further analysis of differentially regulated genes due to bariatric surgery can allow us to explore previously unknown pathways related to breast cancer risk reduction.

Hyperthermia as a Steroidogenic Inhibitor of Adrenodortical Cells, an Adrenal Sparing Treatment for Primary Aldosteronism?

Introduction: Primary Aldosteronism (PA) is the commonest secondary cause of hypertension. Mainstay therapy, adrenalectomy resects both hypersecreting and adjacent normal tissue. It is therefore only suitable for patients with unilateral disease (40% cases), whom are surgical candidates. Thermal therapy presents a plausible minimally invasive therapeutic, to target and disrupt hypersecreting adrenal nodules in primary aldosteronism, while also preserving adjacent normal adrenal cortex. Methodology: Adrenocortical cell lines (H295R and HAC15) were treated with hyperthermia using a water bath at temperatures between 37-650C for 15 minutes. Cell death and apoptosis were analysed immediately, 24 hours, and 48 hours post hyperthermia using Annexin V / Propidium Iodide (PI) (flow cytometry), and Calcein / PI imaging techniques. Steroidogenic potential was also analysed post hyperthermia by (i) measuring cytosolic calcium flux in response to angiotensin II (ANGII) using Flou-4 staining (flow cytometry); (ii) measurement of steroidogenic enzyme expression (RT-PCR); (iii) by measurement of cortisol and aldosterone in cell supernatants (chemiluminescent assays). Cells were also stimulated with forskolin for steroid enzyme and output assays. Results: Hyperthermia induced mainly necrotic cell death not apoptotic. Percentage cell death was significantly increased from 500C-65 0C (95.41+/- 5.74% versus control 9.17+/- 3.01%, p<0.0001). Cytosolic calcium changes in response to ANGII were lowered from 550C-650C in H295R (-36.33+/-7.06 Ca+ Response versus control 10.67+/- 1.76 Ca+ Response, p<0.001) and from 450C-650C in HAC15 (-43.33+/-12.36 Ca+ Response versus control 4.43+/-1.57 Ca+ Response, p<0.002), intracellular stored calcium was also diminished with increased hyperthermia exposures in both cell lines. CYP11B1 (-31.6+/-2.8 ααCt versus control, p<0.0001), CYP11B2 (-11.3+/-4.9 ααCt versus control, p<0.0001), and HSD3B2 (-42+/-9.8 ααCt versus control, p<0.0001) enzyme gene expression was decreased following 450C for 15 minutes in HAC15 cells while only CYP11B2 (-9.3+/-2.5 ααCt versus control, p<0.0001), and HSD3B2 (-15+/-1.3 ααCt versus control, p<0.0001) enzyme gene expression was decreased in H295R cells. Steroid output was also shown to be impaired at 450C for 15 minutes (22.35+/- 4.49 nmol/L versus control 117.7+/- 25 nmol/L, p<0.0001). Conclusion: Hyperthermic therapy delivered at sublethal temperatures and exposure times inhibits steroidogenesis. Inhibiting steroidogenesis by applying targeted thermal therapy to functional adrenocortical nodules represents a novel adrenal sparing approach to definitive management of primary aldosteronism.

Interaction Between Wnt/β-catenin and ACTH Signaling Pathways and Paracrine Regulation in Aldosterone Producing Adenoma

Primary aldosteronism (PA) is the most frequent form of secondary arterial hypertension and is caused in the majority of cases by an aldosterone producing adenoma (APA) or bilateral adrenal hyperplasia. Different somatic mutations have been identified in APA and in other aldosterone producing structures, which can be distinct within the same adrenal, suggesting multiple mechanisms underlying APA development. Also, APA show important cellular and molecular heterogeneity which may be due to interaction of different signaling pathways involved in adrenal cortex cell differentiation and function. The aim of this study was to investigate the role of Wnt/β-catenin and ACTH signaling as well as elements of paracrine regulation of aldosterone biosynthesis and vascularization in the development of APA and aldosterone producing cell clusters (APCC) and their relationship with intratumoral heterogeneity and mutational status. We performed immunohistochemistry and multiplex immunofluorescence (CYP11B2, CYP17A1, β-catenin, MC2R, pCREB, Tryptase, S100, CD34) multispectral image analysis on 11 adrenals with APA and one with micronodular hyperplasia from patients with PA. CYP11B2 (aldosterone synthase) IHC guided RT-qPCR was performed on RNA extracted from formalin-fixed paraffin-embedded tissues in 7 adrenals. Multiplex immunofluorescence revealed high abundance of tryptase positive mast cells and a dense vascular component in APA, which were independent of the mutational status. Within APA, mast cells were mainly localized in zones expressing CYP11B2, but not in areas expressing CYP17A1, and were rarely colocalized with nerve fibers, suggesting that their activity is not controlled by innervation. In cells expressing aldosterone synthase, β-catenin was activated, i.e. shows nuclear and/or cytoplasmic staining, features suggestive of a zona glomerulosa cell identity; MC2R was found at the cell membrane. Expression of MC2R mRNA was observed at different levels in APA, similar to expression of MRAP and VEGFA; MRAP2 was not detected. Within heterogeneous APA carrying KCNJ5 mutations, both MC2R and VEGFA expression was higher in areas expressing CYP11B2. Remarkably, this pattern was maintained in APCC, where cells show high CYP11B2 expression, together with activated β-catenin, independently of the mutation status. In addition, a high number of mast cells was detected around APCC, with a reorganization of the capillaries around the CYP11B2 positive cells. Our results suggest that aldosterone producing structures in adrenals with APA share common molecular characteristics and cellular environment, despite different mutation status. Mast cells appear to be closely associated with cells expressing aldosterone synthase, both in APA and APCC, and their role in regulating aldosterone biosynthesis in the context of somatic mutations in PA remains to be established.

Androstenedione Is the Preferred Substrate for Cytochrome P450 11β-hydroxylase Leading to the Production of 11β-Hydroxyandrostenedione in the Adrenal Gland

Adrenal cytochrome P450 11β-hydroxylase (CYP11B1) is a mitochondrial enzyme that catalyzes the final step of glucocorticoid synthesis, converting 11-deoxycortisol (S) and deoxycorticosterone (DOC) to cortisol (F) and corticosterone (CORT), respectively. CYP11B1 is predominantly located in the zona fasciculata of the adrenal gland with studies also showing that CYP11B1 catalyzes the conversion of androstenedione (A4) and testosterone (T) to 11β-hydroxyandrostenedione (11OHA4) and 11β-hydroxytestosterone (11OHT), respectively. Adrenal vein sampling in women has shown that 11OHA4 turnover is high, with a marked increase after treatment with ACTH which is known to upregulate CYP11B1 expression. We hypothesized that CYP11B1’s affinity for A4 as a substrate may be favored over glucocorticoids since 11OHA4 is one of the major androgens produced in the adrenalThis study aimed to elucidate the kinetic parameters (Km and Vmax) for A4 and T with respect to CYP11B1. A4 and T (0.2 µM to 5 µM) were assayed in HEK-293 cells transiently transfected with CYP11B1 and the adrenodoxin redox partner. Data was used to generate progress curves and fitted to the Michaelis-Menten equation. A4 had the lowest Km (0.21 μM) with a significantly higher Vmax (315.77 pmol/min/mg protein) in comparison to T, S and DOC. Results suggest that A4 binds more readily to CYP11B1 resulting in the high turnover of substrate. The androgenic activity of CYP11B1 catalyzed steroid products was determined using a luciferase assay conducted in CV1 cells. Both A4 and 11OHA4 showed no androgenic activity, however, the 11βHSD2 product of 11OHA4, 11-ketoandrostenedione (11KA4), elicited a response at 100 nM. 11OHT was an androgen receptor (AR) agonist, however, exhibiting a lower response when compared to T and 11-ketotestosterone over all concentrations tested (1, 10 and 100 nM). As confirmation of CYP11B1 activity in the adrenal, circulatory steroid levels were determined in healthy female subjects (n=88). CORT, F and 11OHA4 were measured at a frequency of 70–100%, compared to 11OHT (40–70%), while 11βHSD2 activity produced 11KA4 (<10%). In conclusion, the catalytic efficiency of CYP11B1 towards A4 is higher compared to T and the classical substrates. The high substrate affinity and turnover provides evidence for 11OHA4 in adrenal vein samples. Concurrently, our analysis suggests that agonism is diminished by the presence of the C11- hydroxyl group, while AR agonistic activity is gained upon its conversion to a keto group. Furthermore, these androgens could perhaps modulate cortisol production in the adrenal due to potential competition between precursor substrates.

Very Low‐Density Lipoprotein Signals through Scavenger Receptor Class B Type I And Sphingosine‐1‐Phosphate Receptor 1 to Induce Aldosterone Production, in part, via Lipin‐1 in Human Adrenocortical Cells

Aldosterone is considered to be a link between hypertension and obesity; obese individuals have high serum levels of both very low-density lipoprotein (VLDL) and sphingosine-1-phosphate (S1P). S1P is transported in blood bound to lipoproteins such as VLDL, as well as low-density lipoprotein and high-density lipoprotein (HDL); the VLDL particle contains the highest levels of S1P. S1P in HDL has been shown to promote interactions between scavenger receptor class B type I (SR-BI) and S1P receptor 1 (S1PR1), suggesting the possibility that VLDL, which can also act through SR-BI, may stimulate S1PR1. VLDL has been shown to induce aldosterone production in multiple zona glomerulosa models, mediated in part by phospholipase D (PLD). PLD is an enzyme that hydrolyzes phosphatidylcholine to produce phosphatidic acid (PA), a lipid second messenger that can also be dephosphorylated by lipin-1 to yield diacylglycerol (DAG), yet another lipid second messenger. However, it is unclear which of the two lipid signals, PA or DAG, underlies PLD's mediation of aldosterone production. We hypothesized that upon binding to SR-BI, VLDL signals through S1PR1 to induce aldosterone production, in part, via lipin-1 mediated metabolism of PA to DAG. To determine whether VLDL functions through SR-BI and S1PR1, human adrenocortical (HAC15) cells were treated with VLDL and/or an S1PR1 antagonist (Ex26) for 24 h. The expression of steroidogenic genes and aldosterone production were monitored by qRT-PCR and radioimmunoassay, respectively. Ex26 inhibited VLDL-induced increases in CYP11B2 (22-fold) and StAR (1.5-fold) expression by 43% and 10%, respectively. In addition, the VLDL-induced 5-fold increase in aldosterone levels was significantly inhibited by Ex26 (36%). Our results suggest that VLDL signals by binding to SR-BI and activating S1PR1, since the S1PR1 antagonist reduced VLDL-induced aldosterone production. To assess the role of lipin-1 in VLDL-induced aldosterone production, lipin-1 was overexpressed (using an adenovirus) or inhibited (using propranolol) in HAC15 cells followed by treatment with or without VLDL for 24 h. While lipin-1 overexpression enhanced the VLDL-stimulated 55-fold increase in CYP11B2 expression by 75%, lipin-1 inhibition decreased the VLDL-stimulated 21-fold increase in CYP11B2 expression by 66%. Similarly, the VLDL-stimulated increase in aldosterone production was enhanced by lipin-1 overexpression (182%) and was decreased by lipin-1 inhibition (80%). Our results are suggestive of DAG being the key lipid signal since manipulating lipin-1 levels/activity affects VLDL-stimulated steroidogenic gene expression and ultimately, aldosterone production. Our study warrants further investigation into VLDL-stimulated steroidogenic signaling pathways which may lead to the identification of novel therapeutic targets, such as S1PR1, lipin-1, or their downstream pathways, to potentially treat obesity-associated hypertension.

Aldosterone Insufficiency Contributes to Calcineurin Inhibitor‐induced Hyperkalemia

The mineralocorticoid aldosterone promotes renal K+ excretion and Na+ reabsorption; thereby it is critical for the regulation of ion homeostasis and blood pressure. Interestingly, immunosuppression therapy with protein phosphatase 3 (calcineurin) inhibitors often results in rather low plasma aldosterone levels despite a concomitant hyperkalemia and hyperreninemia. Calcineurin (Cn) is a calcium and calmodulin-dependent protein phosphatase expressed in the adrenal cortex. We tested the hypothesis that Cn participates in the signal transduction pathway mediating the K+-dependent stimulation of aldosterone production. To address this question, we used the adrenocortical cell model NCI-H295R, mouse and human ex vivo adrenal preparations and a ZG-specific and inducible Cn-beta subunit 1 (CnB1) knockout mouse model (ZG-CnB1-KO). Inhibition of Cn with tacrolimus abolished the K+-stimulated expression of CYP11B2 in NCI-H295R cell line as well as in mouse and human adrenal pieces, ex vivo. Moreover, high K+ diet-dependent increase in aldosterone production was blunted in wild type mice treated with tacrolimus. Furthermore, male ZG-CnB1-KO mice fed a high K+ diet exhibited a decreased aldosterone excretion compared to control animals while ZG-CnB1-KO females became hyperkalemic. Using a phosphoproteomics analysis, we identified the nuclear factor of activated T-cells, cytoplasmic 4 (NFATc4) as a downstream factor regulated by Cn. The genetic deletion of NFATc4 in NCI-H295R cells reduced the basal expression of CYP11B2 and blunted the K+-stimulated expression of this gene. Conversely, the expression of a constitutively active form of NFATc4 in NCI-H295R cells drastically increased the expression of CYP11B2 which remained unaltered upon treatment with K+ or tacrolimus. Altogether, our data indicate that the calcineurin-NFATc4 pathway is activated by K+ to promote adrenal aldosterone production. Moreover, our data indicate that insufficient aldosterone production contributes to Cn inhibitor-induced hyperkalemia.

DNA Methylation of the Angiotensinogen Gene, AGT, and the Aldosterone Synthase Gene, CYP11B2 in Cardiovascular Diseases.

Angiotensinogen (AGT) and aldosterone play key roles in the regulation of blood pressure and are implicated in the pathogenesis of cardiovascular diseases. DNA methylation typically acts to repress gene transcription. The aldosterone synthase gene CYP11B2 is regulated by angiotensin II and potassium. DNA methylation negatively regulates AGT and CYP11B2 expression and dynamically changes in response to continuous promoter stimulation of each gene. High salt intake and excess circulating aldosterone cause DNA demethylation around the CCAAT-enhancer-binding-protein (CEBP) sites of the ATG promoter region, thereby converting the phenotype of AGT expression from an inactive to an active state in visceral adipose tissue and heart. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in salt-sensitive hypertensive rats. Salt-dependent hypertension may be partially affected by increased cardiac AGT expression. CpG dinucleotides in the CYP11B2 promoter are hypomethylated in aldosterone-producing adenomas. Methylation of recognition sequences of transcription factors, including CREB1, NGFIB (NR4A1), and NURR1 (NR4A2) diminish their DNA-binding activity. The methylated CpG-binding protein MECP2 interacts directly with the methylated CYP11B2 promoter. Low salt intake and angiotensin II infusion lead to upregulation of CYP11B2 expression and DNA hypomethylation in the adrenal gland. Treatment with the angiotensin II type 1 receptor antagonist decreases CYP11B2 expression and leads to DNA hypermethylation. A close association between low DNA methylation and increased CYP11B2 expression are seen in the hearts of patients with hypertrophic cardiomyopathy. These results indicate that epigenetic regulation of both AGT and CYP11B2 contribute to the pathogenesis of cardiovascular diseases.

Enhanced Ca2+ signaling, mild primary aldosteronism, and hypertension in a familial hyperaldosteronism mouse model (Cacna1hM1560V/+)

Gain-of-function mutations in the CACNA1H gene (encoding the T-type calcium channel CaV3.2) cause autosomal-dominant familial hyperaldosteronism type IV (FH-IV) and early-onset hypertension in humans. We used CRISPR/Cas9 to generate Cacna1hM1560V/+ knockin mice as a model of the most common FH-IV mutation, along with corresponding knockout mice (Cacna1h-/- ). Adrenal morphology of both Cacna1hM1560V/+ and Cacna1h-/- mice was normal. Cacna1hM1560V/+ mice had elevated aldosterone:renin ratios (a screening parameter for primary aldosteronism). Their adrenal Cyp11b2 (aldosterone synthase) expression was increased and remained elevated on a high-salt diet (relative autonomy, characteristic of primary aldosteronism), but plasma aldosterone was only elevated in male animals. The systolic blood pressure of Cacna1hM1560V/+ mice was 8 mmHg higher than in wild-type littermates and remained elevated on a high-salt diet. Cacna1h-/- mice had elevated renal Ren1 (renin-1) expression but normal adrenal Cyp11b2 levels, suggesting that in the absence of CaV3.2, stimulation of the renin-angiotensin system activates alternative calcium entry pathways to maintain normal aldosterone production. On a cellular level, Cacna1hM1560V/+ adrenal slices showed increased baseline and peak intracellular calcium concentrations in the zona glomerulosa compared to controls, but the frequency of calcium spikes did not rise. We conclude that FH-IV, on a molecular level, is caused by elevated intracellular Ca2+ concentrations as a signal for aldosterone production in adrenal glomerulosa cells. We demonstrate that a germline Cacna1h gain-of-function mutation is sufficient to cause mild primary aldosteronism, whereas loss of CaV3.2 channel function can be compensated for in a chronic setting.

ALDOSTERONE CONTRIBUTES TO SYSTOLIC BLOOD PRESSURE ELEVATION DURING REST TIME IN MALE MICE INDUCIBLY OVEREXPRESSING HUMAN ENDOTHELIN-1 IN ENDOTHELIUM

Objective: The mechanisms of blood pressure (BP) regulation by endothelin (ET)-1 produced by endothelial cells (ECs) are complex and remain unclear. Transgenic mice with tamoxifen-inducible EC-restricted human ET-1 overexpression (ieET-1) exhibited BP elevation 3 months after induction. ET-1 has been shown to stimulate the release of aldosterone from adrenal cortex (AC). Whether aldosterone plays a role in EC ET-1 overexpression-induced BP elevation and vascular injury is still unknown. Design and method: Nine to 12-week-old male ieET-1 mice and control ieCre mice expressing a tamoxifen-inducible Cre recombinase under the control of EC-specific Tie2 promoter were treated with tamoxifen (1 mg/kg/day, SC) for 5 days and studied 3 months later. A set of mice was treated with eplerenone (100 mg/kg/day, PO), a mineralocorticoid receptor antagonist, or the ETA receptor blocker atrasentan (100 mg/kg/day) during the last 2 weeks of the study. BP was measured by telemetry and mesenteric artery function and remodeling by pressurized myography. Plasma aldosterone levels were measured by ELISA. The expression of genes involved in aldosterone biosynthesis was determined by reverse transcription-quantitative PCR in AC. CYP11B2 expression was determined in AC by immunofluorescence. Results: Plasma aldosterone levels were increased in ieET-1 vs. ieCre mice (1.21 ± 0.14 vs. 0.70 ± 0.09 ng/mL, P &lt; 0.05), which was reversed by atrasentan. Cyp11b2 (aldosterone synthase), Hsd3b6 (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 6) and Cry1 (core-clock component cryptochrome 1) mRNA expression was decreased respectively by 50%, 39% and 31% in AC, and CYP11B2 protein expression was decreased by 51% in adrenal glomerulosa of ieET-1 vs. ieCre mice (P &lt; 0.05). Two week eplerenone treatment reduced systolic BP by 10 mm Hg in ieET-1 mice during rest time (last 3 days, P &lt; 0.05). Eplerenone abrogated the enhanced sensitivity of mesenteric arteries to contraction by norepinephrine in ieET-1 mice (P &lt; 0.05), increased the sensitivity of endothelium-independent relaxation responses to sodium nitroprusside in ieET-1 mice (P &lt; 0.05). Mesenteric artery media/lumen was reduced in eplerenone-treated ieET-1 vs. ieET-1 and ieCre mice (P &lt; 0.05). Conclusions: These results demonstrate that aldosterone contributes to human EC ET-1 overexpression-induced BP elevation and vascular remodeling and norepinephrine sensitivity.

SOMATIC MUTATIONS IN ADRENALS FROM PATIENTS WITH PRIMARY ALDOSTERONISM NOT CURED AFTER ADRENALECTOMY SUGGEST COMMON PATHOGENIC MECHANISMS BETWEEN UNILATERAL AND BILATERAL DISEASE

Objective: Primary aldosteronism (PA) is the most common form of secondary and curable hypertension, with a prevalence of 5% in primary care and 10% in referred patients. Different germline and somatic mutations are found in aldosterone producing adenoma (APA) and familial forms of the disease, while the causes of bilateral adrenal hyperplasia (BAH) remain largely unknown. Adrenalectomy is the recommended treatment for patients with aldosterone-producing adenoma (APA); however, 6% of patients are not cured and show persistent PA after surgery suggesting BAH. The objective of this study was to analyze clinical data of patients with APA without biochemical success after adrenalectomy and the histological and genetic characteristics of their adrenal glands. Design and method: Clinical data from 16 PA patients undergoing adrenalectomy between 2008 and 2018 without biochemical success were compared to those from 39 PA patients with hormonal cure after surgery. Histological, morphological and genetic characterization of the adrenals was carried out by CYP11B2 and CYP11B1 immunostaining and by CYP11B2 guided next generation sequencing on formalin-fixed paraffin-embedded APA tissues. Results: Patients with absent hormonal cure displayed longer duration of arterial hypertension before PA diagnosis and lower index of lateralization of aldosterone production on adrenal vein sampling. In 14 patients, APA expressing CYP11B2 were identified. No difference in histological and morphological characteristics was observed between patients with our without hormonal cure. Somatic mutations in APA driver genes were identified in 13 out of 14 CYP11B2 positive APA. Mutations in the CACNA1D gene were the most frequent genetic abnormality and associated with smaller nodules. The mutational status of APA in patients without hormonal cure was not associated with differences in CYP11B1 or CYP11B2 expression. Conclusions: In conclusion, 93% of adrenals from patients with absent hormonal cure showed CYP11B2 expressing adenomas carrying somatic mutations, confirming the diagnosis of APA. However, these patients were diagnosed later and exhibited lower lateralization index of aldosterone production, suggesting asymmetric aldosterone production in the context of BAH. Somatic mutations in adrenal glands from those patients indicate common mechanisms underlying BAH and APA.

BIOCHEMICAL, HISTOPATHOLOGICAL, AND GENETIC CHARACTERIZATION OF POSTURE RESPONSIVE AND UNRESPONSIVE ALDOSTERONE-PRODUCING ADENOMAS

Objective: Aldosterone-producing adenoma (APA) accounts for ∼30% of primary aldosteronism. Based on responses of aldosterone to upright posture, APA can be divided into posture-responsive and –unresponsive forms. Somatic gene mutations in KCNJ5, CACNA1D, ATP1A1, or ATP2B3 have been reported to exist in more than 90% of APAs. We sought to compare the biochemical, histopathological, and genetic characterization between these two types of APAs. Design and method: Posture-responsive was defined as showing a rise in plasma aldosterone concentration of at least 50% 2 - 3 h after the assumption of upright posture (10 AM) above the basal level (7 AM) following overnight recumbency. Plasma levels of aldosterone and hybrid steroids (18-oxocortisol and 18-hydroxycortisol) were measured by LC-MS/MS. Histologic analysis and immunohistochemistry for CYP11B2 (aldosterone synthase) and CYP17A1 (17aplha-hydroxylase) were performed on APA tissue sections collected from 24 posture-unresponsive and 17 posture-responsive APA patients. Sanger sequencing of KCNJ5 and gene targeted next-generation sequencing were performed to detect somatic gene mutations. Results: Compared to patients with posture-responsive APA (of which 48.7% were composed of zona glomerulosa (ZG)-like cells and 35.3% showed ZG-zona fasciculata (ZF) mixed appearance), posture-unresponsive APA patients displayed higher (P &lt; 0.01) levels of hybrid steroids, recumbent aldosterone and cortisol, greater (P &lt; 0.05) suppression of aldosterone secretion from the contralateral unaffected adrenal, and larger (P &lt; 0.01) tumors mostly composed of ZF-like cells that had higher (P &lt; 0.01) expression of CYP17A1 (but not of CYP11B2). Of 41 studied APAs, 37 (90.2%) harboured aldosterone-driving somatic mutations (KCNJ5 = 14, 34.1%; CACNA1D = 13, 31.7%; ATP1A1 = 8, 19.5%; and ATP2B3 = 2, 4.9%), including 5 that were previously unreported (3 in CACNA1D and 2 in ATP1A1). Interestingly, 64.7% (11/17) of posture-responsive APAs carried CACNA1D mutations, whereas 54.2% (13/24) of posture-unresponsive APAs harboured KCNJ5 mutations. Conclusions: The excessive production of hybrid steroids by posture-unresponsive APAs may relate to their ZF-like tumor cell composition, resulting in strong expression of CYP17A1 (in addition to somatic gene mutation-driven CYP11B2 expression), thereby allowing production of cortisol which acts as the substrate for CYP11B2-generated hybrid steroids.

Bioinformatics-Based Identification of HDAC Inhibitors as Potential Drugs to Target EGFR Wild-Type Non-Small-Cell Lung Cancer.

Patients with EGFR-mutant non-small-cell lung cancer (NSCLC) greatly benefit from EGFR-tyrosine kinase inhibitors (EGFR-TKIs) while the prognosis of patients who lack EGFR-sensitive mutations (EGFR wild type, EGFR-WT) remains poor due to a lack of effective therapeutic strategies. There is an urgent need to explore the key genes that affect the prognosis and develop potentially effective drugs in EGFR-WT NSCLC patients. In this study, we clustered functional modules related to the survival traits of EGFR-WT patients using weighted gene co-expression network analysis (WGCNA). We used these data to establish a two-gene prognostic signature based on the expression of CYP11B1 and DNALI1 by combining the least absolute shrinkage and selection operator (LASSO) algorithms and Cox proportional hazards regression analysis. Following the calculation of risk score (RS) based on the two-gene signature, patients with high RSs showed a worse prognosis. We further explored targeted drugs that could be effective in patients with a high RS by the connectivity map (CMap). Surprisingly, multiple HDAC inhibitors (HDACis) such as trichostatin A (TSA) and vorinostat (SAHA) that may have efficacy were identified. Also, we proved that HDACis could inhibit the proliferation and metastasis of NSCLC cells in vitro. Taken together, our study identified prognostic biomarkers for patients with EGFR-WT NSCLC and confirmed a novel potential role for HDACis in the clinical management of EGFR-WT patients.

Effects of 1,25 and 24,25 Vitamin D on Corneal Fibroblast VDR and Vitamin D Metabolizing and Catabolizing Enzymes

ABSTRACT Purpose: To investigate the effects of 1,25-Vit D3 and 24,25-Vit D3 on corneal fibroblast expression of the vitamin D-associated enzymes CYP27B1 and CYP24A1 and the roles of the vitamin D receptor (VDR) and protein disulfide isomerase, family A, member 3 (Pdia3) in these cells. Methods: CYP24A1, CYP27B1, VDR, and Pdia3 expression in corneas was detected using immunohistochemistry. Western blotting was used to measure protein expression in human and mouse fibroblasts, including VDR KO mouse cells, treated with 1,25-Vit D3 (20 nM) and 24,25-Vit D3 (100 nM). The Pdia3 inhibitor LOC14 was used to explore the role of Pdia3 as a Vit D3 receptor in these cells. Results: CYP24A1, CYP27B1, VDR, and Pdia3 were all expressed in mouse and human corneal fibroblasts. 1,25-Vit D3 significantly increased VDR expression in human and mouse fibroblasts. 1,25-Vit D3 and 24,25-VitD3 significantly increased CYP24A1 and CYP27B1 expression level in human, VDR WT mouse, and VDR KO mouse corneal fibroblasts. CYP24A1 and CYP27B1 expression was unchanged in VDR KO mouse fibroblasts treated with 1,25-Vit D3 or 24,25-Vit D3 plus LOC14. Human fibroblast VDR, CYP24A1, and CYP27B1 expression were unaffected by LOC14. Conclusions: Vitamin D metabolic enzymes, VDR, and Pdia3 are all expressed in mouse and human corneal fibroblasts. 1,25-Vit D3 modulates fibroblast vitamin D enzymes through both the VDR and Pdia3 pathways in a species-dependent manner. 24,25-Vit D3 can increase expression of fibroblast CYP24A1 and CYP27B1 in the absence of VDR and is likely involved in fibroblast regulation independent of 1,25-Vit D3 or VDR.

Effect of potassium on DNA methylation of aldosterone synthase gene.

Aldosterone synthase gene, CYP11B2 is regulated by potassium and angiotensin II (Ang II). We have reported that Ang II could change the DNA methylation status around transcription factor-binding sites and a transcription start site (TSS) and activate expression of CYP11B2. Similar to Ang II, small increases in extracellular potassium levels also increase CYP11B2 mRNA levels. Adrenocortical H295R cells were treated with different doses of potassium. Methylation analysis of CYP11B2 promoter region was done by bisulfite sequencing. CYP11B2 mRNA and protein levels, chromatin accessibility, methylation and demethylation activity were estimated. The transcriptional ability of CYP11B2 promoter with or without methylation was assessed. Potassium stimulation caused DNA demethylation around cyclic AMP responsive element binding protein 1 (CREB1) and nuclear receptor subfamily 4 group A (NR4A) family-binding sites and a TSS; demethylation was accompanied by recruitment of CREB1 and NR4A1 and increased chromatin accessibility of the CYP11B2 promoter. DNA methylation activity decreased in the nucleus. DNA demethylation at CpG1 (Ad1), CpG2 (Ad5) and CpG3 were detected within 2 to 4 days after potassium (16 mmol/l) stimulation. The changes reached a maximum level by day 7. DNA at CpG2 (Ad5) and CpG3 was re-methylated to levels that were similar to those of nontreated cells at day 9. Potassium treatment significantly reduced DNA methylation activity at days 7 and 9. DNA demethylation activity was not changed by potassium. : Potassium induced reversibly DNA demethylation, which switches the phenotype of CYP11B2 expression from an inactive to an active state.

Functional Characteristic and Significance of Aldosterone-Producing Cell Clusters in Primary Aldosteronism and Age-Related Hypertension.

Primary aldosteronism (PA) is one of the most frequent curable forms of secondary hypertension. It can be caused by the overproduction of aldosterone in one or both adrenal glands. The most common subtypes of PA are unilateral aldosterone over-production due to aldosterone-producing adenomas (APA) or bilateral aldosterone over-production due to bilateral hyperaldosteronism (BHA). Utilizing the immunohistochemical (IHC) detection of aldosterone synthase (CYP11B2) has allowed the identification of aldosterone-producing cell clusters (APCCs) with unique focal localization positive for CYP11B2 expression in the subcapsular portion of the human adult adrenal cortex. The presence of CYP11B2 supports that synthesis of aldosterone can occur in these cell clusters and therefore might contribute to hyperaldosteronism. However, the significance of the steroidogenic properties of APCCs especially in regards to PA remains unclear. Herein, we review the available evidence on the presence of APCCs in normal adrenals and adrenal tissues adjacent to APAs, their aldosterone-stimulating somatic gene mutations, and their accumulation during the ageing process; raising the possibility that APCCs may play a role in the development of PA and age-related hypertension.

Flow-dependent differentiation of cultured adrenal cells under different stimuli.

It still remains unclear how the functional organisation of the adrenal cortex arises. One aim of this study was to create a setup which allows for the establishment of a concentration gradient in vitro. This was achieved by a continuous flow of medium through the culture flask which caused differences in glucose and cortisol concentrations as well as in pH values between the sites of inflow and outflow of medium. Using real-time polymerase chain reaction, we found that a continuous supply of 1ml medium per hour significantly increased the expression of MC2R, CYP11B1 and CYP17A1 genes of NCI-H295R cells in the distal area of the flask as compared with the proximal part. The expression of the AT1R showed a reverse regulation. The addition of dexamethasone to the medium led to an increase in gene expression of MC2R while AT1R was downregulated. Moreover, we detected a higher expression of CYP11B2 and a decreased expression of CYP11B1 when endothelial cell-conditioned medium (ECCM) was added to the inflow. Our experiments show that a directed medium delivery system creates different gradients and affects the functional differentiation of the NCI-H295R cells. Also, our results emphasise that products of endothelial cells have additional effects on the differentiation of the cultured adrenal cortical cells. Our results are in support that the regulation of the adrenal zonation is possible through different concentration gradients.

Aldosterone and cortisol synthesis regulation by angiotensin-(1-7) and angiotensin-converting enzyme 2 in the human adrenal cortex.

The branch of the renin--angiotensin system constituting angiotensin-(1-7) [Ang-(1-7)], the Ang II type 2 receptor, the Mas receptors and the Ang-(1-7)-forming enzyme ACE-2, by counteracting the Ang II type 1 receptor (AT1R)-mediated effects, are held to be cardiovascular protective in several conditions. However, whether Ang-(1-7) and ACE-2 are detectable in human adrenocortical tissues and whether they affect aldosterone and cortisol biosynthesis was unknown. We measured angiotensin peptides with liquid chromatography tandem-mass spectrometry and ACE-2 mRNA with digital droplet (dd)PCR in human aldosterone-producing adenoma (APA) and APA-adjacent tissue obtained from patients with primary aldosteronism. We also investigated the effects of Ang-(1-7) and the ACE-2 activator diminazene aceturate (DIZE) on aldosterone synthase (CYP11B2) and 11β-hydroxylase (CYP11B1) gene expression, in the absence or presence of the AT1R antagonist irbesartan, or of the MasR antagonist A779. APA and APA-adjacent adrenocortical tissues express ACE-2 mRNA and contain detectable amounts of Ang II and Ang-(2-8), but not of Ang I, Ang-(1-5), Ang (3-8) and Ang-(1-7). Under unstimulated and Ang II- stimulated conditions Ang-(1-7) did not blunt CYP11B1 and CYP11B2 mRNA. At supraphysiological concentrations (10-4 mol/l), Ang-(1-7) stimulated both CYP11B1 and CYP11B2 mRNA via the AT1R. The ACE-2 activator DIZE increased by 1.5-fold ACE-2 mRNA but did not blunt Ang II- upregulated CYP11B1 and CYP11B2 expression. These results do not support the hypothesis that the ACE-2/Ang-(1-7)/MasR axis play a protective role by counteracting enhanced aldosterone secretion in humans.

Chlorpyrifos alters expression of enzymes involved in vitamin D3 synthesis in skin cells

Skin acts as a mechanical barrier between human body and environment. Epidermal cells are regularly exposed to many physiological and environmental stressors, such as pesticides, like chlorpyrifos (CPS). It is recognised that CPS may affect metabolism of other exo- and endogenous substances by affecting enzyme activity and expression. This study aims to investigate the effect of CPS on expression of CYP27A1, CYP27B1 and CYP24A1, the enzymes involved in synthesis and metabolism of vitamin D3, in human keratinocytes HaCaT and human fibroblasts BJ. Synthesis of vitamin D3 in cells was initiated by irradiating with UVB. Expression of CYP27A1, CYP27B1 and CYP24A1 was evaluated by RT-qPCR and Western blot. Our experiments revealed that expression of all tested cytochrome P450 isoforms in cells exposed to CPS changed significantly. Exposure of HaCaT keratinocytes to CPS decreased CYP27A1 mRNA levels, but increased CYP27B1 and CYP24A1 mRNA levels. This was confirmed at the protein level, except for the CYP27A1 expression. Outcome for the BJ cells was however less conclusive. Though exposure to CPS decreased CYP27A1 and CYP27B1 mRNA levels, at protein level increasing concentration of CPS and UVB intensity induced expression of CYP27A1 and CYP24A1. The expression of CYP27B1 isoform decreased in line with mRNA level. Nevertheless, it can be concluded that CPS may therefore interrupt vitamin D3 metabolism in skin cells, but further studies are required to better understand such mechanisms.