Genetically predicted plasma cortisol and common chronic diseases: A Mendelian randomization study.

OBJECTIVE: Cushing's syndrome is characterized by hypercortisolaemia and is frequently accompanied by comorbidities such as type 2 diabetes, hypertension, osteoporosis, depression and schizophrenia. It is unclear whether moderate but lifelong hypercortisolaemia is causally associated with these diseases in the general population. We aimed to address this research gap using a Mendelian randomization approach. METHODS: We used three cortisol-associated genetic variants in the SERPINA6/SERPINA1 region as genetic instruments in a two-sample, inverse-variance-weighted Mendelian randomization analysis. We obtained summary-level statistics for cortisol and disease outcomes from publicly available genetic consortia, and meta-analysed them as appropriate. We conducted a multivariable Mendelian randomization analysis to assess potential mediating effects. RESULTS: A 1 standard deviation higher genetically predicted plasma cortisol was associated with greater odds of hypertension (odds ratio: 1.12; 95% confidence interval [CI]: 1.05-1.18) as well as higher systolic blood pressure (mean difference [MD]: 0.03 SD change; 95% CI: 0.01-0.05) and diastolic blood pressure (MD: 0.03 SD change; 95% CI: 0.01-0.04). There was no evidence of association with type 2 diabetes, osteoporosis, depression and schizophrenia. The association with hypertension was attenuated upon adjustment for waist circumference, suggesting potential mediation through central obesity. CONCLUSION: There is strong evidence for a causal association between plasma cortisol and greater risk for hypertension, potentially mediated by obesity.

Rare correlation of somatic PRKACA mutations with pregnancy-associated aldosterone- and cortisol-producing adenomas: a case report and literature review.

BACKGROUND: Somatic mutations have been observed to induce aldosterone-producing adenomas (APAs). These may be accelerated during pregnancy. Somatic PRKACA mutations are common in cortisol-producing adenomas (CPAs). However, their role in APAs, particularly aldosterone- and cortisol-producing adenomas (A/CPAs), is not well understood. This study aims to investigate the association between PRKACA mutations and the accelerated development of A/CPAs during pregnancy. CASE PRESENTATION: A patient with primary aldosteronism (PA) associated with severe Cushing's syndrome (CS) underwent surgical resection of an adrenal tumor one year after delivery. Pathologic examination revealed an adrenocortical adenoma characterized primarily by zona glomerulosa hyperplasia. Somatic mutation analysis revealed the presence of the somatic PRKACA mutation, which was validated as a deleterious mutation by various computational databases. Immunohistochemical results showed positive staining for cytochrome P450 family 11 subfamily B member 1 (CYP11B1), cytochrome P450 family 11 subfamily B member 2 (CYP11B2), and luteinizing hormone/chorionic gonadotropin receptor (LHCGR). Our study included a review of 20 previously documented cases of aldosterone- and cortisol-producing adenomas (A/CPAs), two of which were concurrently positive for both CYP11B1 and CYP11B2, consistent with our findings. CONCLUSION: Somatic mutations in PRKACA may correlate with the upregulation of LHCGR, which synergistically drives the accelerated growth of co-secretion tumors during pregnancy, thereby exacerbating disease progression.

Circulating myomiRNAs as biomarkers in patients with Cushing's syndrome.

PURPOSE: Impairment of skeletal muscle mass and strength affects 40-70% of patients with active Cushing's syndrome (CS). Glucocorticoid excess sustains muscle atrophy and weakness, while muscle-specific microRNAs (myomiRs) level changes were associated with muscle organization and function perturbation. The aim of the current study is to explore changes in circulating myomiRs in CS patients compared to healthy controls and their involvement in IGFI/PI3K/Akt/mTOR pathway regulation in skeletal muscle. METHODS: C2C12, mouse myocytes, were exposed to hydrocortisone (HC), and atrophy-related gene expression was investigated by RT-qPCR, WB and IF to assess HC-mediated atrophic signalling. miRNAs were evaluated in HC-treated C2C12 by PCR Arrays. MyomiRs significantly overexpressed in C2C12 were investigated in 37 CS patients and 24 healthy controls serum by RT-qPCR. The anti-anabolic role of circulating miRNAs significantly upregulated in CS patients was explored in C2C12 by investigating the IGFI/PI3K/Akt/mTOR pathway regulation. RESULTS: HC induced higher expression of atrophy-related genes, miR-133a-3p, miR-122-5p and miR-200b-3p in C2C12 compared to untreated cells. Conversely, the anabolic IGFI/PI3K/Akt/mTOR signalling was reduced and this effect was mediated by miR-133a-3p. In CS patients miR-133a-3p and miR-200b-3p revealed higher circulating levels (p < 0.0001, respectively) compared to controls. ROC curves for miR-133a-3p (AUC 0.823, p < 0.0001) and miR-200b-3p (AUC 0.850, p < 0.0001) demonstrated that both myomiRs represent potential biomarkers to discriminate between CS and healthy subjects. Pearson's correlation analysis revealed that circulating levels of miR-133a-3p are directly correlated with 24 h urinary-free cortisol level (r = 0.468, p = 0.004) in CS patients. CONCLUSIONS: HC induces atrophic signals by miR-133a-3p overexpression in mouse myocytes and humans. Circulating miR-133a-3p is promising biomarkers of hypercortisolism.

Cardiovascular risk assessments in patients with cortisol-producing adenoma: impact of clinical features and genetic characteristics.

The causes of adrenal Cushing's syndrome (CS) encompass a wide spectrum of adrenal cortisol proliferations that exhibit clinical and molecular heterogeneity. The aims of our study were to investigate whether clinical and molecular heterogeneity influences endothelial function and metabolic abnormalities in patients with cortisol-producing adenoma (CPA). We retrospectively enrolled 25 patients with CPA and 45 patients with essential hypertension (EH). All CPAs were studied by direct sequencing of PRKACA. Flow-mediated vasodilation (FMD), an index of vascular endothelial function, was significantly lower in CS and subclinical CS (SCS) groups than in the EH group. FMD impairment did not differ significantly between CS and SCS groups. No differences in FMD were seen between PRKACA mutant and wild-type groups. FMD correlated negatively with hemoglobin A1c (HbA1c) in both PRKACA mutant and wild-type groups, as well as in CS and SCS groups. After adrenalectomy, systolic blood pressure (SBP) and HbA1c decreased significantly from baseline in the CS group, and SBP and low-density lipoprotein cholesterol (LDL-C) decreased significantly from baseline in the SCS group. While SBP and LDL-C decreased significantly from baseline in patients with wild-type PRKACA, only HbA1c decreased from baseline in patients harboring PRKACA mutations. Our data showed that patients with CPA have impaired endothelial function compared with EH patients and suggest the need for strict monitoring of atherosclerosis, even in patients with SCS or without PRKACA mutation.

Classification of Cushing's syndrome PKAc mutants based upon their ability to bind PKI.

Cushing's syndrome is an endocrine disorder caused by excess production of the stress hormone cortisol. Precision medicine strategies have identified single allele mutations within the PRKACA gene that drive adrenal Cushing's syndrome. These mutations promote perturbations in the catalytic core of protein kinase A (PKAc) that impair autoinhibition by regulatory subunits and compartmentalization via recruitment into AKAP signaling islands. PKAcL205R is found in ∼45% of patients, whereas PKAcE31V, PKAcW196R, and L198insW and C199insV insertion mutants are less prevalent. Mass spectrometry, cellular, and biochemical data indicate that Cushing's PKAc variants fall into two categories: those that interact with the heat-stable protein kinase inhibitor PKI, and those that do not. In vitro activity measurements show that wild-type PKAc and W196R activities are strongly inhibited by PKI (IC50 < 1 nM). In contrast, PKAcL205R activity is not blocked by the inhibitor. Immunofluorescent analyses show that the PKI-binding variants wild-type PKAc, E31V, and W196R are excluded from the nucleus and protected against proteolytic processing. Thermal stability measurements reveal that upon co-incubation with PKI and metal-bound nucleotide, the W196R variant tolerates melting temperatures 10°C higher than PKAcL205. Structural modeling maps PKI-interfering mutations to a ∼20 Šdiameter area at the active site of the catalytic domain that interfaces with the pseudosubstrate of PKI. Thus, Cushing's kinases are individually controlled, compartmentalized, and processed through their differential association with PKI.

Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) patient with ARMC5 mutations.

BACKGROUND: Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is a highly heterogeneous disease with divergent manifestations ranging from asymptomatic subclinical Cushing syndrome (CS) to overt Cushing syndrome with severe complications. ARMC5 mutations occur in 20 to 55% PBMAH patients usually with more severe phenotypes. Different ARMC5 mutations might be associated with diverse phenotypes of PBMAH. CASE PRESENTATION: A 39-year-old man was admitted to our hospital with progressive weight gain and severe hypertension. He presented typical CS and its classical metabolic and bone complications like hypertension and osteoporosis. The laboratory results showed high levels of cortisol and low levels of ACTH. Low- and high-dosed dexamethasone suppression tests were negative. Contrast-enhanced computed tomography (CT) revealed multiple bilateral irregular macronodular adrenal masses. Adrenal venous sampling (AVS) confirmed that the right adrenal gland with larger nodules secreted more hormone that the left side did. Right adrenalectomy and subsequent contralateral subtotal resection were conducted. His blood pressure and CS symptoms as well as comorbidities including backache and muscle weakness improved. Whole exome sequencing identified one ARMC5 germline mutation (c.1855C > T, p. R619*), five ARMC5 somatic mutations (four novel mutations) in his right and left adrenal nodules. CONCLUSIONS: This PBMAH patient was identified with one ARMC5 germline mutation and five different somatic ARMC5 mutations (four novel mutations) in the different nodules of the bilateral adrenal masses. AVS combined with CT imagine could be helpful to determine the dominant side for adrenalectomy. Genetic testing is important for the diagnosis and management of the patient with PBMAH.

A case report and literature review of Carney complex with atrial adenomyxoma.

BACKGROUND: Carney complex (CNC) is a rare multiple endocrine neoplasia syndrome characterized by mucocutaneous lentigines/ blue nevi, cardiac myxoma and endocrine overactivity. Here, we report a CNC case with PRKAR1A gene mutation characterized by left atrial adenomyxoma to explore the diagnosis and treatment of CNC. CASE PRESENTATION: A 42-year-old woman with a history of cardiac tumour surgery presented with typical features of Cushing syndrome, including central obesity, buffalo hump, mild facial plethora, purple striae on the lower abdomen, and spotty skin pigmentation. Left atrial adenomyxoma and thyroid papillary carcinoma were identified by postoperative histologic assays. Genetic screening revealed a pathogenic germline heterozygous mutation of c.682C > T (p.R228X) in exon 7 of the PRKAR1A gene. The clinical features and normal ACTH levels suggest this patient suffered the ACTH-independent primary pigmented nodular adrenocortical disease (PPNAD) with cyclic hypercortisolism or ACTH-dependent Cushing syndrome. CONCLUSION: CNC is uncommon, however, if a patient develops clinical features involving multiple endocrine and non-endocrine tumors, especially Cushing syndrome and cardiac myxoma, CNC should be considered. Genetic analysis is recommended in patients with suspected CNC.

Cushing syndrome and glucocorticoids: T-cell lymphopenia, apoptosis, and rescue by IL-21.

BACKGROUND: Pediatric endogenous Cushing syndrome (eCs) is mainly caused by pituitary corticotropin-producing adenomas, and most glucocorticoid-dependent effects progressively regress upon tumor removal. eCs reproduces long-term, high-dose glucocorticoid therapy, representing a clean, natural, and unbiased model in which to study glucocorticoid bona fide effects on immunity. OBJECTIVE: We performed extensive immunologic studies in otherwise healthy pediatric patients with eCs before and 6 to 13 months after tumor resection, as well as in in vitro glucocorticoid-treated control cells. METHODS: Flow cytometry, immunoblotting, enzyme-linked immunosorbent assay, real-time quantitative PCR, and RNA-Seq techniques were used to characterize patients' and in vitro glucocorticoid treated cells. RESULTS: Reduced thymic output, decreased naive T cells, diminished proliferation, and increased T-cell apoptosis were detected before surgery; all these defects eventually normalized after tumor removal in patients. In vitro studies also showed increased T-cell apoptosis, with correspondingly diminished NF-κB signaling and IL-21 levels. In this setting, IL-21 addition upregulated antiapoptotic BCL2 expression and rescued T-cell apoptosis in a PI3K pathway-dependent manner. Similar and reproducible findings were confirmed in eCs patient cells as well. CONCLUSIONS: We identified decreased thymic output and lymphocyte proliferation, together with increased apoptosis, as the underlying causes to T-cell lymphopenia in eCs patients. IL-21 was decreased in both natural and in vitro long-term, high-dose glucocorticoid environments, and in vitro addition of IL-21 counteracted the proapoptotic effects of glucocorticoid therapy. Thus, our results suggest that administration of IL-21 in patients receiving long-term, high-dose glucocorticoid therapy may contribute to ameliorate lymphopenia and the complications associated to it.

KDM1A inactivation causes hereditary food-dependent Cushing syndrome.

PURPOSE: This study aimed to investigate the genetic cause of food-dependent Cushing syndrome (FDCS) observed in patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) and adrenal ectopic expression of the glucose-dependent insulinotropic polypeptide receptor. Germline ARMC5 alterations have been reported in about 25% of PBMAH index cases but are absent in patients with FDCS. METHODS: A multiomics analysis of PBMAH tissues from 36 patients treated by adrenalectomy was performed (RNA sequencing, single-nucleotide variant array, methylome, miRNome, exome sequencing). RESULTS: The integrative analysis revealed 3 molecular groups with different clinical features, namely G1, comprising 16 patients with ARMC5 inactivating variants; G2, comprising 6 patients with FDCS with glucose-dependent insulinotropic polypeptide receptor ectopic expression; and G3, comprising 14 patients with a less severe phenotype. Exome sequencing revealed germline truncating variants of KDM1A in 5 G2 patients, constantly associated with a somatic loss of the KDM1A wild-type allele on 1p, leading to a loss of KDM1A expression both at messenger RNA and protein levels (P = 1.2 × 10-12 and P < .01, respectively). Subsequently, KDM1A pathogenic variants were identified in 4 of 4 additional index cases with FDCS. CONCLUSION: KDM1A inactivation explains about 90% of FDCS PBMAH. Genetic screening for ARMC5 and KDM1A can now be offered for most PBMAH operated patients and their families, opening the way to earlier diagnosis and improved management.

MicroRNA expression signature and target prediction in familial and sporadic primary macronodular adrenal hyperplasia (PMAH).

BACKGROUND: Primary macronodular adrenal hyperplasia (PMAH), previously termed ACTH-independent macronodular adrenal hyperplasia (AIMAH), is a rare cause of Cushing's syndrome usually characterized by functioning adrenal macronodules and increased cortisol production. METHODS: To screen and analyse the microRNA (miRNA) profile of PMAH in order to elucidate its possible pathogenesis, a miRNA microarray was used to test tissue samples from patients with familial PMAH, patients with sporadic PMAH and normal control samples of other nontumour adrenocortical tissues and identify characteristic microRNA expression signatures. Randomly selected miRNAs were validated by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Furthermore, the key signalling pathways and miRNAs involved in PMAH pathogenesis were determined by gene ontology and pathway analysis. RESULTS: Characteristic microRNA expression signatures were identified for patients with familial PMAH (16 differentially expressed microRNAs) and patients with sporadic PMAH (8 differentially expressed microRNAs). The expression of the selected miRNAs was confirmed by qRT-PCR, suggesting the high reliability of the miRNA array analysis results. Pathway analysis showed that the most enriched pathway was the renal cell carcinoma pathway. Overexpression of miR-17, miR-20a and miR-130b may inhibit glucocorticoid-induced apoptosis in PMAH pathogenesis. CONCLUSION: We identified the miRNA signatures in patients with familial and sporadic PMAH. The differentially expressed miRNAs may be involved in the mechanisms of PMAH pathogenesis. Specific miRNAs, such as miR-17, miR-20a and miR-130b, may be new targets for further functional studies of PMAH.

A novel pathogenic variant of ARMC5 in a patient with primary bilateral macronodular adrenal hyperplasia: a case report.

BACKGROUND: Primary bilateral macronodular adrenal hyperplasia (PBMAH), also known as adrenocorticotropic hormone (ACTH)-independent macronodular adrenal hyperplasia, is a rare cause of endogenous Cushing's syndrome. In many familial cases of PBMAH, the variants in armadillo repeat containing 5 (ARMC5) gene are found to be associated with the disease. Here, we report a case of PBMAH harboring a novel frameshift variant in ARMC5 gene, which has not been previously reported in the literature. CASE PRESENTATION: A 67-year-old woman was referred due to the clinical features of Cushing's syndrome. Radiological imaging and hormonal testing were carried out. The serum levels of cortisol were remarkably increased at late night and did not suppress even after 1 mg of dexamethasone administration, while the plasma levels of ACTH hormone were decreased significantly. The patient underwent unilateral left-sided laparoscopic adrenalectomy, and the diagnosis of PBMAH was substantiated by histopathological analysis. Moreover, the partial envelope was incomplete and the cell proliferation index was low. Specifically, inhibin α-subunit ( +), syn focal ( +), Ki-67 ~ 3% ( +), CgA (-) and CEA (-) were observed. DNA sequencing data revealed that a novel frameshift variant (c.363_373delGCCAGTGCGCC, p.Pro122Alafs*61) was identified in ARMC5 gene. However, this variant was not detected in the daughter of the patient. The rest of the family members, including her sister, son and two brothers, were not consented for genetic testing. CONCLUSIONS: Early detection of ARMC5 variant status and familial screening might have important clinical implications for the diagnosis and prognosis of PBMAH patients. A novel ARMC5 frameshift variant (c.363_373delGCCAGTGCGCC, p.Pro122Alafs*61) was identified to be associated with the pathogenesis of PBMAH. ARMC5 sequencing may improve the identification of a causative gene variant for PBMAH and allow earlier diagnosis of this disease.

Cushing's disease in children: unique features and update on genetics.

In this brief report, we review the unique characteristics of Cushing disease (CD) in children, as well as the most important new genetic discoveries associated with childhood CD. We often forget it, but CD refers to Cushing syndrome caused by pituitary corticotroph adenomas only. Thus, here we only refer to the new discoveries associated with pituitary tumors. There is indeed a wealth of new information on clinical features, outcomes, and genetic determinants of CD in children!

Phenotypic Variability in a Family with Carney Complex Accompanied by a Novel Mutation Involving PRKAR1A.

Carney complex is a rare, autosomal dominant disease accompanied by multiple endocrine neoplastic syndromes. Mutations in the PRKAR1A gene have recently been reported as a cause of Carney complex, but genotype-phenotype correlations vary widely. A 15-year-old Japanese man (Case 1) with short stature visited our hospital with suspected Cushing's syndrome. Biochemical investigations suggested corticotropin-independent Cushing's syndrome. Computed tomography revealed multiple bilateral adrenal tumors, and a two-staged partial adrenalectomy was performed. Pathological findings revealed primary pigmented nodular adrenocortical disease (PPNAD). The patient also exhibited distinctive spotty skin pigmentation. Based on these features, the patient was diagnosed as Carney complex. Cascade screening of family members was performed, and the mother (Case 2) and elder brother (Case 3) were diagnosed as Carney complex. Case 2 showed cardiac myxoma, acromegaly, spotty skin pigmentation, and mammary myxoid fibroadenoma. Case 3 exhibited gigantism, spotty skin pigmentation, and thyroid nodules. Target gene testing in Case 1 and 2 revealed the same novel mutation in PRKAR1A gene (c.503G>T, p.Gly168Val). This mutation was predicted as a pathogenic variant by multiple in silico analyses. Here, we present a family of Carney complex cases with a novel PRKAR1A pathogenic variant exhibiting varied clinical phenotypes within each case. In these cases, some specific phenotypes of Carney complex, such as pigmentary disorders, myxomas, and PPNAD are important as clues for diagnosis and prognostic factors. Clinicians should consider further examination in patients with Carney complex-specific phenotypes.

Pathophysiology of Mild Hypercortisolism: From the Bench to the Bedside.

Mild hypercortisolism is defined as biochemical evidence of abnormal cortisol secretion without the classical detectable manifestations of overt Cushing's syndrome and, above all, lacking catabolic characteristics such as central muscle weakness, adipose tissue redistribution, skin fragility and unusual infections. Mild hypercortisolism is frequently discovered in patients with adrenal incidentalomas, with a prevalence ranging between 5 and 50%. This high variability is mainly due to the different criteria used for defining this condition. This subtle cortisol excess has also been described in patients with incidentally discovered pituitary tumors with an estimated prevalence of 5%. To date, the mechanisms responsible for the pathogenesis of mild hypercortisolism of pituitary origin are still not well clarified. At variance, recent advances have been made in understanding the genetic background of bilateral and unilateral adrenal adenomas causing mild hypercortisolism. Some recent data suggest that the clinical effects of glucocorticoid (GC) exposure on peripheral tissues are determined not only by the amount of the adrenal GC production but also by the peripheral GC metabolism and by the GC sensitivity. Indeed, in subjects with normal cortisol secretion, the combined estimate of cortisol secretion, cortisone-to-cortisol peripheral activation by the 11 beta-hydroxysteroid dehydrogenase enzyme and GC receptor sensitizing variants have been suggested to be associated with the presence of hypertension, diabetes and bone fragility, which are three well-known consequences of hypercortisolism. This review focuses on the pathophysiologic mechanism underlying both the different sources of mild hypercortisolism and their clinical consequences (bone fragility, arterial hypertension, subclinical atherosclerosis, cardiovascular remodeling, dyslipidemia, glucose metabolism impairment, visceral adiposity, infections, muscle damage, mood disorders and coagulation).

Genetic Basis of ACTH-Secreting Adenomas.

Cushing's disease represents 60-70% of all cases of Cushing's syndrome, presenting with a constellation of clinical features associated with sustained hypercortisolism. Molecular alterations in corticotrope cells lead to the formation of ACTH-secreting adenomas, with subsequent excessive production of endogenous glucocorticoids. In the last few years, many authors have contributed to analyzing the etiopathogenesis and pathophysiology of corticotrope adenomas, which still need to be fully clarified. New molecular modifications such as somatic mutations of USP8 and other genes have been identified, and several case series and case reports have been published, highlighting new molecular alterations that need to be explored. To investigate the current knowledge of the genetics of ACTH-secreting adenomas, we performed a bibliographic search of the recent scientific literature to identify all pertinent articles. This review presents the most recent updates on somatic and germline mutations underlying Cushing's disease. The prognostic implications of these mutations, in terms of clinical outcomes and therapeutic scenarios, are still debated. Further research is needed to define the clinical features associated with the different genotypes and potential pharmacological targets.

Characterization of Adrenal miRNA-Based Dysregulations in Cushing's Syndrome.

MiRNAs are important epigenetic players with tissue- and disease-specific effects. In this study, our aim was to investigate the putative differential expression of miRNAs in adrenal tissues from different forms of Cushing's syndrome (CS). For this, miRNA-based next-generation sequencing was performed in adrenal tissues taken from patients with ACTH-independent cortisol-producing adrenocortical adenomas (CPA), from patients with ACTH-dependent pituitary Cushing's disease (CD) after bilateral adrenalectomy, and from control subjects. A confirmatory QPCR was also performed in adrenals from patients with other CS subtypes, such as primary bilateral macronodular hyperplasia and ectopic CS. Sequencing revealed significant differences in the miRNA profiles of CD and CPA. QPCR revealed the upregulated expression of miR-1247-5p in CPA and PBMAH (log2 fold change > 2.5, p < 0.05). MiR-379-5p was found to be upregulated in PBMAH and CD (log2 fold change > 1.8, p < 0.05). Analyses of miR-1247-5p and miR-379-5p expression in the adrenals of mice which had been exposed to short-term ACTH stimulation showed no influence on the adrenal miRNA expression profiles. For miRNA-specific target prediction, RNA-seq data from the adrenals of CPA, PBMAH, and control samples were analyzed with different bioinformatic platforms. The analyses revealed that both miR-1247-5p and miR-379-5p target specific genes in the WNT signaling pathway. In conclusion, this study identified distinct adrenal miRNAs as being associated with CS subtypes.

Genomic and sequence variants of protein kinase A regulatory subunit type 1ß (PRKAR1B) in patients with adrenocortical disease and Cushing syndrome.

PURPOSE: Protein kinase A (PKA) subunit defects (in PRKAR1A and PRKACA) are known to contribute to adrenal tumor pathogenesis. We studied the PRKAR1B gene for any genetic changes in bilateral adrenocortical hyperplasia (BAH) and cortisol-producing adrenal adenomas (CPA). METHODS: Exome sequencing and PRKAR1B copy-number variant (CNV) analysis were performed in 74 patients with BAH and 21 with CPA. PKA activity was studied in tumors with defects; sequence variants were investigated in vitro. RESULTS: Three PRKAR1B germline variants (p.I40V, p.A67V, p.A300T) were identified among 74 patients with BAH. PRKAR1B copy-number gains (CNG) were found in 3 of 21 CPAs, one in a tumor carrying a somatic PRKACA "hotspot" pathogenic variant p.L206R. CPAs bearing PRKAR1B CNGs showed higher PRKAR1B messenger RNA (mRNA) levels and reduced PKA activity. Baseline PKA activity was also decreased for p.A67V and p.A300T in vitro, and mutant PRKAR1ß bound PRKACα in fluorescence resonance energy transfer (FRET) recordings of cotransfected HEK293 cells stronger than normal. CONCLUSION: PRKAR1B is yet another PKA subunit that may potentially contribute to adrenal tumor formation. Its involvement in adrenocortical disease may be different from that of other subunits, because PRKAR1B variants and PRKAR1B CNGs were associated with decreased (rather than increased) overall PKA activity in vitro.

Wnt-Signaling Regulated by Glucocorticoid-Induced miRNAs.

Glucocorticoids (GCs) are pleiotropic hormones which regulate innumerable physiological processes. Their comprehensive effects are due to the diversity of signaling mechanism networks. MiRNAs, small, non-coding RNAs contribute to the fine tuning of signaling pathways and reciprocal regulation between GCs and miRNAs has been suggested. Our aim was to investigate the expressional change and potential function of GC mediated miRNAs. The miRNA expression profile was measured in three models: human adrenocortical adenoma vs. normal tissue, steroid-producing H295R cells and in hormonally inactive HeLa cells before and after dexamethasone treatment. The gene expression profile in 82 control and 57 GC-affected samples was evaluated in GC producing and six different GC target tissue types. Tissue-specific target prediction (TSTP) was applied to identify the most relevant miRNA-mRNA interactions. Glucocorticoid treatment resulted in cell type-dependent miRNA expression changes. However, 19.5% of the influenced signaling pathways were common in all three experiments, of which the Wnt-signaling pathway seemed to be the most affected. Transcriptome data and TSTP showed similar results, as the Wnt pathway was significantly altered in both the GC-producing adrenal gland and all investigated GC target tissue types. In different cell types, different miRNAs led to the regulation of similar pathways. Wnt signaling may be one of the most important signaling pathways affected by hypercortisolism. It is, at least in part, regulated by miRNAs that mediate the glucocorticoid effect. Our findings on GC producing and GC target tissues suggest that the alteration of Wnt signaling (together with other pathways) may be responsible for the leading symptoms observed in Cushing's syndrome.

Update of Genetic and Molecular Causes of Adrenocortical Hyperplasias Causing Cushing Syndrome.

Bilateral hyperplasias of the adrenal cortex are rare causes of chronic endogenous hypercortisolemia also called Cushing syndrome. These hyperplasias have been classified in two categories based on the adrenal nodule size: the micronodular types include Primary Pigmented Nodular Adrenocortical Disease (PPNAD) and isolated Micronodular Adrenal Disease (iMAD) and the macronodular also named Primary Bilateral Macronodular Adrenal Hyperplasia (PBMAH). This review discusses the genetic and molecular causes of these different forms of hyperplasia that involve mutations and dysregulation of various regulators of the cAMP/protein kinase A (PKA) pathway. PKA signaling is the main pathway controlling cortisol secretion in adrenocortical cells under ACTH stimulation. Although mutations of the regulatory subunit R1α of PKA (PRKAR1A) is the main cause of familial and sporadic PPNAD, inactivation of two cAMP-binding phosphodiesterases (PDE11A and PDE8B) are associated with iMAD even if they are also found in PPNAD and PBMAH cases. Interestingly, PBMAH that is observed in multiple familial syndrome such as APC, menin, fumarate hydratase genes, has initially been associated with the aberrant expression of G-protein coupled receptors (GPCR) leading to an activation of cAMP/PKA pathway. However, more recently, the discovery of germline mutations in Armadillo repeat containing protein 5 (ARMC5) gene in 25-50% of PBMAH patients highlights its importance in the development of PBMAH. The potential relationship between ARMC5 mutations and aberrant GPCR expression is discussed as well as the potential other causes of PBMAH.

A putative role for the aryl hydrocarbon receptor (AHR) gene in a patient with cyclical Cushing's disease.

BACKGROUND: Apart from PRKAR1A mutations in a subset of cyclical Cushing's syndrome due to primary pigmented nodular adrenocortical disease, the molecular basis of cyclical Cushing's syndrome has not been investigated. We speculated that cyclical Cushing's syndrome may be due to mutations in the clock genes that govern circadian rhythms, including the hypothalamic-pituitary-adrenal axis. CASE PRESENTATION: A 47-year-old man presented with mass effects from a sellar lesion. He was ultimately diagnosed with cyclical Cushing's disease due to a giant corticotrophinoma. We performed whole exome sequencing of germline and tumour DNA, SNP array of tumour DNA and tumour immunohistochemistry in order to detect variants in candidate circadian/pituitary-associated genes. We identified a rare germline missense variant in the aryl hydrocarbon receptor (AHR) gene, which has previously been indirectly linked to pituitary tumorigenesis and clock system disruption. The AHR variant was found in a highly conserved site involved in phosphorylation. It was predicted to be damaging by multiple in silico tools and AHR tumour immunohistochemistry demonstrated loss of the normal nuclear staining pattern, suggestive of an inactivating mutation. We also found a novel, damaging germline missense variant in the retinoid X receptor gamma (RXRG) gene, multiple somatic chromosomal gains (including AHR), and a somatic mutational signature consistent with oncogenesis that may have acted synergistically with the AHR variant. CONCLUSIONS: This is the first report of an AHR variant with predicted pathogenicity in the pituitary adenoma setting. Our preliminary data suggest that the highly conserved AHR gene may represent a link between pituitary tumorigenesis, the hypothalamic-pituitary-adrenal axis and the clock system. Further research may indicate a role for the gene in the development of cyclical Cushing's disease.