Age-dependent effects of Armc5 haploinsufficiency on adrenocortical function.

Inactivating mutations in the Armadillo repeat-containing 5 (ARMC5) gene have recently been discovered in primary macronodular adrenal hyperplasia (PMAH), a cause of Cushing syndrome. Biallelic ARMC5 inactivation in PMAH suggested that ARMC5 may have tumor suppressor functions in the adrenal cortex. We generated and characterized a new mouse model of Armc5 deficiency. Almost all Armc5 knockout mice died during early embryonic development, around 6.5 and 8.5 days. Knockout embryos did not undergo gastrulation, as demonstrated by the absence of mesoderm development at E7.5. Armc5 heterozygote mice (Armc5+/-) developed normally but at the age of 1 year, their corticosterone levels decreased; this was associated with a decrease of protein kinase A (PKA) catalytic subunit α (Cα) expression both at the RNA and protein levels that were also seen in human patients with PMAH and ARMC5 defects. However, this was transient, as corticosterone levels normalized later, followed by the development of hypercorticosteronemia in one-third of the mice at 18 months of age, which was associated with increases in PKA and Cα expression. Adrenocortical tissue analysis from Armc5+/- mice at 18 months showed an abnormal activation of the Wnt/ß-catenin signaling pathway in a subset of zona fasciculata cells. These data confirm that Armc5 plays an important role in early mouse embryonic development. Our new mouse line can be used to study tissue-specific effects of Armc5. Finally, Armc5 haploinsufficiency leads to Cushing syndrome in mice, but only later in life, and this involves PKA, its catalytic subunit Cα, and the Wnt/ß-catenin pathway.

Hageman factor C46T promoter gene polymorphism in patients with hypercortisolism.

Glucocorticoids are a group of hormones with a particularly significant effect on hemostasis. In hypercortisolemic patients increased concentrations of II, VIII, and von Willebrand factors were reported. Considerably fewer studies were concerned with factor XII (FXII). There are reports of decreased FXII concentrations in both venous and arterial thrombosis patients. Also, it was determined that FXII C46T promoter gene polymorphism leads to changes of its concentration. The aim of the study was to determine the C46T polymorphism of FXII promoter gene in hypercortisolemic patients. Thirty hypercortisolemic patients were enrolled in the study. Twenty-nine healthy individuals served as controls. Genomic DNA was isolated from peripheral blood leukocytes. To analyse the polymorphism, PCR products were digested by Hga I at 37°C for 23 h, subjected to 2% agarose gel, and stained with ethidium bromide. In all subjects FXII activity was determined using a clot-based method. All statistical calculations were performed using STATA 12.0 software. A p-value lower than 0.05 was considered statistically significant. Prevalence of FXII C46T polymorphism did not differ significantly between hypercortisolemic patients and controls. No correlation was found between FXII activity and its gene promoter polymorphism in the hypercortisolemic group; however, a clear trend was recorded toward higher FXII activities in 46C homozygotes, and lower in 46T homozygotes. Mean FXII activities did not differ significantly between hypercortisolemic patients and the control group. It seems that in hypercortisolemic patients no significant disorders are present concerning FXII concentrations due to the C46T polymorphism of its gene promoter.

Hypertension with or without adrenal hyperplasia due to different inherited mutations in the potassium channel KCNJ5.

We recently implicated two recurrent somatic mutations in an adrenal potassium channel, KCNJ5, as a cause of aldosterone-producing adrenal adenomas (APAs) and one inherited KCNJ5 mutation in a Mendelian form of early severe hypertension with massive adrenal hyperplasia. The mutations identified all altered the channel selectivity filter, producing increased Na(+) conductance and membrane depolarization, the signal for aldosterone production and proliferation of adrenal glomerulosa cells. We report herein members of four kindreds with early onset primary aldosteronism of unknown cause. Sequencing of KCNJ5 revealed that affected members of two kindreds had KCNJ5(G151R) mutations, identical to one of the prevalent recurrent mutations in APAs. These individuals had severe progressive aldosteronism and hyperplasia requiring bilateral adrenalectomy in childhood for blood pressure control. Affected members of the other two kindreds had KCNJ5(G151E) mutations, which are not seen in APAs. These subjects had easily controlled hypertension and no evidence of hyperplasia. Surprisingly, electrophysiology of channels expressed in 293T cells demonstrated that KCNJ5(G151E) was the more extreme mutation, producing a much larger Na(+) conductance than KCNJ5(G151R), resulting in rapid Na(+)-dependent cell lethality. We infer that this increased lethality limits adrenocortical cell mass and the severity of aldosteronism in vivo, accounting for the milder phenotype among these patients. These findings demonstrate striking variations in phenotypes and clinical outcome resulting from different mutations of the same amino acid in KCNJ5 and have implications for the diagnosis and pathogenesis of primary aldosteronism with and without adrenal hyperplasia.

Activation of cyclic AMP signaling leads to different pathway alterations in lesions of the adrenal cortex caused by germline PRKAR1A defects versus those due to somatic GNAS mutations.

CONTEXT: The overwhelming majority of benign lesions of the adrenal cortex leading to Cushing syndrome are linked to one or another abnormality of the cAMP or protein kinase pathway. PRKAR1A-inactivating mutations are responsible for primary pigmented nodular adrenocortical disease, whereas somatic GNAS activating mutations cause macronodular disease in the context of McCune-Albright syndrome, ACTH-independent macronodular hyperplasia, and, rarely, cortisol-producing adenomas. OBJECTIVE AND DESIGN: The whole-genome expression profile (WGEP) of normal (pooled) adrenals, PRKAR1A- (3) and GNAS-mutant (3) was studied. Quantitative RT-PCR and Western blot were used to validate WGEP findings. RESULTS: MAPK and p53 signaling pathways were highly overexpressed in all lesions against normal tissue. GNAS-mutant tissues were significantly enriched for extracellular matrix receptor interaction and focal adhesion pathways when compared with PRKAR1A-mutant (fold enrichment 3.5, P < 0.0001 and 2.1, P < 0.002, respectively). NFKB, NFKBIA, and TNFRSF1A were higher in GNAS-mutant tumors (P < 0.05). Genes related to the Wnt signaling pathway (CCND1, CTNNB1, LEF1, LRP5, WISP1, and WNT3) were overexpressed in PRKAR1A-mutant lesions. CONCLUSION: WGEP analysis revealed that not all cAMP activation is the same: adrenal lesions harboring PRKAR1A or GNAS mutations share the downstream activation of certain oncogenic signals (such as MAPK and some cell cycle genes) but differ substantially in their effects on others.

Hyperphosphatasemia and concurrent adrenal gland dysfunction in apparently healthy Scottish Terriers.

OBJECTIVE: To determine causes of hyperphosphatasemia (high serum alkaline phosphatase [ALP] activity) in apparently healthy Scottish Terriers. DESIGN: Prospective case-controlled study. ANIMALS: 34 apparently healthy adult Scottish Terriers (17 with and 17 without hyperphosphatasemia). PROCEDURES: Serum activities for 3 isoforms (bone, liver, and corticosteroid) of ALP were measured. Concentrations of cortisol, progesterone, 17-hydroxyprogesterone, androstenedione, estradiol, and aldosterone were measured before and after cosyntropin administration (ie, ACTH; 5 microg/kg [2.27 microg/lb], IM). Liver biopsy specimens from 16 dogs (11 with and 5 without hyperphosphatasemia) were evaluated histologically. RESULTS: In dogs with hyperphosphatasemia, the corticosteroid ALP isoform comprised a significantly higher percentage of total ALP activity, compared with the percentage in dogs without hyperphosphatasemia (mean +/- SE, 69 +/- 5.0% and 17 +/- 3.8%, respectively). In 6 dogs with hyperphosphatasemia, but none without, serum cortisol concentrations exceeded reference intervals after ACTH stimulation. Six dogs with and 15 without hyperphosphatasemia had increased concentrations of >or = 1 noncortisol steroid hormone after ACTH stimulation. Serum ALP activity was correlated with cortisol and androstenedione concentrations (r = 0.337 and 0.496, respectively) measured after ACTH stimulation. All dogs with and most without hyperphosphatasemia had abnormal hepatocellular reticulation typical of vacuolar hepatopathy. Subjectively, hepatocellular reticulation was more severe and widespread in hyperphosphatasemic dogs, compared with that in nonhyperphosphatasemic dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Hyperphosphatasemia in apparently healthy Scottish Terriers was most likely attributable to hyperadrenocorticism on the basis of exaggerated serum biochemical responses to ACTH administration and histologic hepatic changes, but none of the dogs had clinical signs of hyperadrenocorticism.

Pituitary tumour-transforming gene (PTTG) and pituitary senescence.

Pituitary tumours account for 15% of intracranial neoplasms and are benign monoclonal neoplasms that may be clinically silent or secrete hormones, including prolactin, growth hormone, adrenocorticotrophic hormone or, rarely, thyroid-stimulating hormone or gonadotrophins. These adenomas account for clinical infertility, growth disorders and hypercortisolism or metabolic dysfunctions associated with hypopituitarism. We explored the role of disordered pituitary cell proliferation control in the pathogenesis of these invariably benign adenomas, studying the mechanisms underlying pituitary aneuploidy, premature proliferative arrest (senescence), markers of cell proliferation and tumorigenesis in single, double or triply mutant transgenic mice with mutations of Rb, Pttg and/or p21. Our results provide further insights into the role of cell-cycle control and growth constraints on experimental and human pituitary tumours, which underlie their failure to progress to malignancy. These results improve our understanding of pituitary syndromes associated with infertility, growth disorders, hypercortisolism or adrenal, thyroid and gonadal failure due to abrogated pituitary function.

[Familial canine pituitary-dependent hyperadrenocorticism in wirehaired Dachshunds]. / Familiäres Auftreten des kaninen hypophysären Hyperadrenokortizismus beim Rauhaardackel.

Canine pituitary hyperadrenocorticism (Cushing's disease) caused by neoplasia of the corticotrope cells is one of the most common endocrine diseases especially in smaller dog breeds. Cushing's disease was diagnosed in eleven wire-haired Dachshunds and for further six wire-haired Dachshunds Cushing's disease was suspected on the basis of clinical signs. A joined pedigree could be ascertained for all these 17 dogs. Eleven of these dogs were so closely related to each other, that they were summarized in four nucleus families. Two fullsiblings were examined by means of clinical, laboratory diagnostic and morphological methods. The main lesions consisted of atrophic dermatosis with alopecia, increase of activity of liver enzymes in plasma and bilateral adrenocortical hyperplasia and therefore corresponded to the typical signs of a secondary hyperadrenocorticism. A rather unusual finding was the pituitary carcinoma in one of these dogs. Similarly to human patients affected by hyperadrenocorticism, real-time PCR analysis showed a 2.9-fold increase of expression of the canine MDR1 gene in the liver of one affected wirehaired Dachshund. This study documents the first familial occurrence of pituitary-dependent hyperadrenocorticism in wirehaired Dachshunds, the overexpression of the MDR1 gene in the dog and the third case of familial hyperadrenocorticism in dogs ever described.

Adrenal hyperplasia and adenomas are associated with inhibition of phosphodiesterase 11A in carriers of PDE11A sequence variants that are frequent in the population.

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A) gene. We now studied the frequency of two missense substitutions, R804H and R867G, in conserved regions of the enzyme in several sets of normal controls, including 745 individuals enrolled in a longitudinal cohort study, the New York Cancer Project. In the latter, we also screened for the presence of the previously identified PDE11A nonsense mutations. R804H and R867G were frequent among patients with adrenocortical tumors; although statistical significance was not reached, these variants affected significantly enzymatic function in vitro with variable increases in cAMP and/or cyclic guanosine 3',5'-monophosphate levels in HeLa and HEK293 cells. Adrenocortical tissues carrying the R804H mutation showed 2q allelic losses and higher cyclic nucleotide levels and cAMP-responsive element binding protein phosphorylation. We conclude that missense mutations of the PDE11A gene that affect enzymatic activity in vitro are present in the general population; protein-truncating PDE11A mutations may also contribute to a predisposition to other tumors, in addition to their association with adrenocortical hyperplasia. We speculate that PDE11A genetic defects may be associated with adrenal pathology in a wider than previously suspected clinical spectrum that includes asymptomatic individuals.

Genetic information in the diagnosis and treatment of hypertension.

Advancement in cardiovascular science should be measured by a number of new diagnostic and therapeutic options applied in clinical practice as a result of translational research. Hypertension genetics is a good example of such a successful transfer of knowledge from bench to bedside. There are genetic methods currently used as diagnostic tools in patients presenting with secondary forms of hypertension, including primary hyperaldosteronism, Cushing's syndrome, pheochromocytoma, and chronic kidney disease. Directed treatment that corrects pathophysiologic abnormalities is available for several monogenic forms of hypertension as a result of uncovering their underlying genetic mechanisms. Progress in hypertension pharmacogenetics and pharmacogenomics brings closer a perspective of personalized antihypertensive treatment and gene transfer strategies, which, although still considered as innovative approaches, may soon become options to treat, control, and, possibly, cure hypertension.

Androgen excess in women--a health hazard?

A significant body of evidence suggests that androgens in women may play a role in the genesis of central adiposity and type 2 diabetes. There are two principal sources of circulating androgens in females: the ovary and the adrenal gland. In hyperandrogenic women, there are elevated serum concentrations of androstenedione and testosterone and, in up to 50% of the women, dehydroepiandrosterone sulfate (DHEAS). The androgen precursor DHEAS is of exclusive adrenal origin, suggesting that hyperandrogenic women have an elevated proportion of adrenal androgen production and secretion. Another cause of androgen excess in reproductive-age women is a decreased conversion of testosterone to estradiol by the aromatase enzyme complex. In this review, we will discuss the hypothesized clinical sequel of elevated androgens in women - an aspect of women's health highly neglected. Furthermore, an attempt is made to appreciate what causes the androgens to initially rise from normal levels, allowing the onset of pathophysiological processes towards diseases.

Glucocorticoid resistance and hypersensitivity.

This article emphasizes the disorders caused by mutations and polymorphisms of the alpha form of the glucocorticoid receptor. These disorders usually present with increased circulating cortisol concentrations and must be distinguished from Cushing's syndrome, because the therapies are markedly different. The other disorders present with clinical features limited to a specific organ system. Although they illustrate important physiologic and pathophysiologic principles, they usually are not confused with Cushing's syndrome.

Cushing's syndrome secondary to adrenocorticotropin-independent macronodular adrenocortical hyperplasia due to activating mutations of GNAS1 gene.

ACTH-independent macronodular adrenal hyperplasia (AIMAH) is an uncommon cause of Cushing's syndrome characterized by bilateral nodular adrenocortical hyperfunction in the presence of suppressed ACTH levels. We investigated whether activating mutations in the ACTH receptor (MC2-R) or G(s alpha) (GNAS1) genes might be involved in AIMAH genesis. Five women with Cushing's syndrome due to AIMAH, confirmed by histological studies, and no signs of McCune-Albright syndrome were selected for molecular analysis of these genes. The single exon of the MC2-R gene and exons 8 and 9 of the GNAS1 gene were amplified by PCR in genomic DNA from adrenal nodules and peripheral blood. Direct sequencing revealed only MC2-R wild-type sequences. GNAS1 PCR products at denaturing gradient gel electrophoresis revealed abnormal migration patterns in adrenal tissues of three patients. Automatic sequencing showed two different activating mutations at codon Arg(201) of GNAS1, a substitution by histidine in two cases and by serine in one case. In conclusion, we found two different gsp mutations in three patients with Cushing's syndrome due to AIMAH, and we speculate whether they belong to the spectrum of McCune-Albright syndrome or whether these are the first reported cases of AIMAH due to gsp mutations.

Familial/sporadic glucocorticoid resistance syndrome and hypertension.

Glucocorticoids regulate diverse functions important for the maintenance of central nervous system, cardiovascular, metabolic, and immune homeostasis. The actions of these hormones are mediated by the specific intracellular glucocorticoid receptors (GRs). Pathologic conditions associated with changes of tissue sensitivity to these hormones have been described. The syndrome of familial/sporadic glucocorticoid resistance is characterized by hypercortisolism without Cushing syndrome stigmata. Many of the patients present with hypertension, with or without hypokalemic alkalosis, as a result of elevated concentrations of cortisol and other salt-retaining steroids. The molecular defects of 4 kindreds and one sporadic case have been elucidated as inactivating mutations in the ligand-binding domain of the GR. In two patients in whom the GR was mutated at amino acid isoleucine 559 to aspartic acid (GRalphaI559N) and isoleucine 747 to methionine (GRalphaI747M), respectively, glucocorticoid resistance developed at the heterozygous state, with transdominant negative activity of each of the mutant receptors upon the wild-type protein. Retention of the wild-type receptor in the cytoplasm by the mutant receptor was found in the former, while inappropriate accumulation of p160-type coactivators on the promoter region of glucocorticoid-responsive genes, because of a defective interaction between the AF2 region of the mutant receptor and the LXXLL motif of the coactivators, was determined in the latter. These results suggest that the pathologic mechanisms of glucocorticoid resistance is quite broad, and this is reflected in the wide variability of the clinical picture in patients with the syndrome.

Heterozygous mutation in the cholesterol side chain cleavage enzyme (p450scc) gene in a patient with 46,XY sex reversal and adrenal insufficiency.

Cytochrome P450scc, the mitochondrial cholesterol side chain cleavage enzyme, is the only enzyme that catalyzes the conversion of cholesterol to pregnenolone and, thus, is required for the biosynthesis of all steroid hormones. Congenital lipoid adrenal hyperplasia is a severe disorder of steroidogenesis in which cholesterol accumulates within steroidogenic cells and the synthesis of all adrenal and gonadal steroids is impaired, hormonally suggesting a disorder in P450scc. However, congenital lipoid adrenal hyperplasia is caused by mutations in the steroidogenic acute regulatory protein StAR; it has been thought that P450scc mutations are incompatible with human term gestation, because P450scc is needed for placental biosynthesis of progesterone, which is required to maintain pregnancy. In studying patients with congenital lipoid adrenal hyperplasia, we identified an individual with normal StAR and SF-1 genes and a heterozygous mutation in P450scc. The mutation was found in multiple cell types, but neither parent carried the mutation, suggesting it arose de novo during meiosis, before fertilization. The patient was atypical for congenital lipoid adrenal hyperplasia, having survived for 4 yr without hormonal replacement before experiencing life-threatening adrenal insufficiency. The P450scc mutation, an in-frame insertion of Gly and Asp between Asp271 and Val272, was inserted into a catalytically active fusion protein of the P450scc system (H2N-P450scc-Adrenodoxin Reductase-Adrenodoxin-COOH), completely inactivating enzymatic activity. Cotransfection of wild-type and mutant vectors showed that the mutation did not exert a dominant negative effect. Because P450scc is normally a slow and inefficient enzyme, we propose that P450scc haploinsufficiency results in subnormal responses to ACTH, so that recurrent ACTH stimulation leads to a slow accumulation of adrenal cholesterol, eventually causing cellular damage. Thus, although homozygous absence of P450scc should be incompatible with term gestation, haploinsufficiency of P450scc causes a late-onset form of congenital lipoid adrenal hyperplasia that can be explained by the same two-hit model that has been validated for congenital lipoid adrenal hyperplasia caused by StAR deficiency.

Síndrome de Cushing secundario a displasia adrenal micronodular familiar / Familial micronodular adrenal dysplasia originating Cushing's sindrome

Dos hermanas (14 y 18 años) estudiadas por hipercortisolismo en nuestro servicio en el último año presentaron datos analíticos y bioquímicos de síndrome de Cushing independiente del ACTH, aun cuando los estudios de localización realizados no pudieron poner de manifiesto un agrandamiento uni o bilateral de las glándulas adrenales. En sus antecedentes figuraba una tía materna con hallazgos "similares". La clínica de hipercortisolismo sólo fue evidente en la mayor de las hermanas, mientras que la hiperfunción adrenal fue demostrada tras un estudio de secreción espontánea en 24 h en la más pequeña. Fueron remitidas a cirugía siendo practicada en ambas una adrenalectomía bilateral. El estudio anatomopatológico reveló la presencia de múltiples nódulos entre 1 y 3 mm, de coloración oscura y atrofia perinodular confirmando la existencia de displasia micronodular pigmentaria. No se objetivaron datos de presencia de síndrome de Carney en ellas. Presentamos la clínica, los hallazgos analíticos e histológicos de nuestras pacientes afectadas de esta inusual enfermedad y una revisión de la bibliografía científica (AU)

Expression of hsp90 beta messenger ribonucleic acid in patients with familial glucocorticoid resistance--correlation to receptor status.

We have previously shown an increased specific DNA-binding of liganded unactivated glucocorticoid receptor (GR) to the LTR-region of MMTV DNA in a patient with primary cortisol resistance and receptor thermolability indicating a defective interaction of GR with hsp90. In some patients, however, no apparent receptor abnormality was found in spite of a characteristic phenotype. mRNA expression levels of hsp90 beta were analysed in cultured fibroblasts from patients with known receptor defects, such as thermolability, decreased ligand binding affinity and low receptor expression levels, and from patients with a cortisol resistant phenotype but no detected receptor alteration. Fibroblasts from patients with GR defects expressed higher hsp90 beta mRNA levels as compared to patients with no receptor defects or to healthy controls. These data indicate that GR defects are associated with increased hsp90 beta mRNA levels.

Point mutations of ras genes in human adrenal cortical tumors: absence in adrenocortical hyperplasia.

Point mutations of ras genes (K-, H-, and N-ras) at codons 12, 13, and 61 and of the Gi2 alpha gene at codons 179 and 205, were studied in 56 primary adrenal cortical tumors and 6 adrenal cortical hyperplasias. Of 56 tumors, 24 were carcinomas and 32 were benign. The 24 carcinomas and 20 of the benign tumors were from American patients; the 12 remaining adenomas were from Japanese patients. Of the benign tumors 12 were cortisol-producing adenomas, 15 were aldosterone-producing adenomas, 3 were nonfunctioning adenomas, and 2 were adenomas that produced a virilizing syndrome. Tumor DNA obtained from archival formalin-fixed, paraffin-embedded tissue or fresh frozen tissue was amplified by polymerase chain reaction; and point mutations were detected by sequence-specific oligonucleotide hybridization. Activating ras mutations were found in 7 of 56 (12.5%) of all tumors: 3 of 24 (12.5%) carcinomas and 4 of 32 (12.5%) adenomas. Of adenomas from an American population, 4 of 20 (20%) exhibited positive ras mutations, whereas none was present in the Japanese tumors. All mutations detected were adenine to guanine transitions at the second position of N-ras codon 61, resulting in a conversion from glutamine to arginine. No mutations were found in K-ras or H-ras genes. Furthermore, no mutations of the Gi2 alpha gene were identified. These findings demonstrate that N-ras mutations at codon 61 may contribute to the genesis of both benign and malignant human adrenal cortical tumors. Finally, no mutations of the ras or Gi2 alpha genes were identified in hyperplastic adrenocortical tissues.