Adipose tissue in cortisol excess: What Cushing's syndrome can teach us?

Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation.

Cushing Syndrome Is Associated With Gut Microbial Dysbiosis and Cortisol-Degrading Bacteria.

CONTEXT: Cushing syndrome (CS) is a severe endocrine disease characterized by excessive secretion of cortisol with multiple metabolic disorders. While gut microbial dysbiosis plays a vital role in metabolic disorders, the role of gut microbiota in CS remains unclear. OBJECTIVE: The objective of this work is to examine the alteration of gut microbiota in patients with CS. METHODS: We performed shotgun metagenomic sequencing of fecal samples from 78 patients with CS and 78 healthy controls matched for age and body mass index. Furthermore, we verify the cortisol degradation capacity of Ruminococcus gnavus in vitro and identify the potential metabolite by LC-MC/MS. RESULTS: We observed significant differences in microbial composition between CS and controls in both sexes, with CS showing reduced Bacteroidetes (Bacteroides vulgatus) and elevated Firmicutes (Erysipelotrichaceae_bacterium_6_1_45) and Proteobacteria (Enterobacter cloacae). Despite distinct causes of hypercortisolism in ACTH-dependent and ACTH-independent CS, we found no significant differences in metabolic profiles or gut microbiota between the 2 subgroups. Furthermore, we identified a group of gut species, including R. gnavus, that were positively correlated with cortisol levels in CS. These bacteria were found to harbor cortisol-degrading desAB genes and were consistently enriched in CS. Moreover, we demonstrated the efficient capacity of R. gnavus to degrade cortisol to 11-oxygenated androgens in vitro. CONCLUSION: This study provides evidence of gut microbial dysbiosis in patients with CS and identifies a group of CS-enriched bacteria capable of degrading cortisol. These findings highlight the potential role of gut microbiota in regulating host steroid hormone levels, and consequently host health.

Toward Systems-Level Metabolic Analysis in Endocrine Disorders and Cancer.

Metabolism is a dynamic network of biochemical reactions that support systemic homeostasis amidst changing nutritional, environmental, and physical activity factors. The circulatory system facilitates metabolite exchange among organs, while the endocrine system finely tunes metabolism through hormone release. Endocrine disorders like obesity, diabetes, and Cushing's syndrome disrupt this balance, contributing to systemic inflammation and global health burdens. They accompany metabolic changes on multiple levels from molecular interactions to individual organs to the whole body. Understanding how metabolic fluxes relate to endocrine disorders illuminates the underlying dysregulation. Cancer is increasingly considered a systemic disorder because it not only affects cells in localized tumors but also the whole body, especially in metastasis. In tumorigenesis, cancer-specific mutations and nutrient availability in the tumor microenvironment reprogram cellular metabolism to meet increased energy and biosynthesis needs. Cancer cachexia results in metabolic changes to other organs like muscle, adipose tissue, and liver. This review explores the interplay between the endocrine system and systems-level metabolism in health and disease. We highlight metabolic fluxes in conditions like obesity, diabetes, Cushing's syndrome, and cancers. Recent advances in metabolomics, fluxomics, and systems biology promise new insights into dynamic metabolism, offering potential biomarkers, therapeutic targets, and personalized medicine.

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.

Impact of Morphology in the Genotype and Phenotype Correlation of Bilateral Macronodular Adrenocortical Disease (BMAD): A Series of Clinicopathologically Well-Characterized 35 Cases.

Bilateral macronodular adrenocortical disease (BMAD) is characterized by the development of adrenal macronodules resulting in a pituitary-ACTH independent Cushing's syndrome. Although there are important similarities observed between the rare microscopic descriptions of this disease, the small series published are not representative of the molecular and genetic heterogenicity recently described in BMAD. We analyzed the pathological features in a series of BMAD and determined if there is correlation between these criteria and the characteristics of the patients. Two pathologists reviewed the slides of 35 patients who underwent surgery for suspicion of BMAD in our center between 1998 and 2021. An unsupervised multiple factor analysis based on microscopic characteristics divided the cases into 4 subtypes according to the architecture of the macronodules (containing or not round fibrous septa) and the proportion of the different cell types: clear, eosinophilic compact, and oncocytic cells. The correlation study with genetic revealed subtype 1 and subtype 2 are associated with the presence of ARMC5 and KDM1A pathogenic variants, respectively. By immunohistochemistry, all cell types expressed CYP11B1 and HSD3B1. HSD3B2 staining was predominantly expressed by clear cells whereas CYP17A1 staining was predominant on compact eosinophilic cells. This partial expression of steroidogenic enzymes may explain the low efficiency of cortisol production in BMAD. In subtype 1, trabeculae of eosinophilic cylindrical cells expressed DAB2 but not CYP11B2. In subtype 2, KDM1A expression was weaker in nodule cells than in normal adrenal cells; alpha inhibin expression was strong in compact cells. This first microscopic description of a series of 35 BMAD reveals the existence of 4 histopathological subtypes, 2 of which are strongly correlated with the presence of known germline genetic alterations. This classification emphasizes that BMAD has heterogeneous pathological characteristics that correlate with some genetic alterations identified in patients.

Extensive expertise in endocrinology: glucose-dependent insulinotropic peptide-dependent Cushing's syndrome.

Thirty years ago, we identified that cortisol secretion in some patients with unilateral adenoma or primary bilateral macronodular adrenal hyperplasia (PBMAH) was stimulated by food intake; this was secondary to the abnormal adrenocortical responsiveness to physiological post-prandial increase in glucose-dependent insulinotropic peptide (GIP). This resulted from the ectopic expression of non-mutated GIP receptor in the pathological adrenal tissues of those patients. Although ectopic GIP receptor (GIPR) was confirmed in a relatively limited number of cases to date, its elucidation leads to the identification of a wide diversity of aberrant G-protein-coupled receptors regulating steroidogenesis and cell proliferation in a high proportion of patients with PBMAH or cortisol-secreting adenomas. In addition, ectopic GIPR was identified in other endocrine tumors including somatotroph pituitary tumors with paradoxical growth hormone response to oral glucose, medullary thyroid carcinomas, and other neuroendocrine tumors. The first molecular pathogenic mechanism responsible for ectopic GIPR expression was elucidated in unilateral GIP-dependent adenomas in which somatic duplication and rearrangements in chromosome region 19q13.32 containing the GIPR locus lead to increased expression of GIPR which was enhanced by the activity of a glucocorticoid response element. Recently, germline lysine demythylase 1A (KDMIA) mutations combined with somatic chromosome 1p deletions were found to be specifically responsible for ectopic GIPR in sporadic or familial GIP-dependent PBMAH and can be associated with adrenal myelolipoma, monoclonal gammopathy of unknown significance (MGUS), or multiple myeloma. Screening for ectopic GIPR should be conducted in all patients with PBMAH; genetic studies to identify KDM1A mutations should be offered to such patients in order to detect affected members and provide early detection of PBMAH and other potential associated neoplasias. The elucidation of GIP-dependent Cushing's syndrome (CS) illustrates that careful bedside phenotyping of rare conditions can lead to identification of genetically determined diseases requiring personalized approaches to investigation and therapy.

Proteomics and Metabolomics Analysis Reveals the Toxicity of ZnO Quantum Dots on Human SMMC-7721 Cells.

Purpose: ZnO quantum dots (QDs) are composed of less toxic metals than other QDs but have the same interesting photochemical properties. Thus, they have received considerable attention recently. Nevertheless, their toxicity cannot be ignored. Methods: In this study, we incubated ZnO QDs with human SMMC-7721 cells for 24 h to assess their nanotoxicity through proteomics (Fold change >1.5 and p-value <0.05) and metabolomics (Fold change ≥ 1.5; VIP ≥ 1; p-value < 0.05) analyses. Results: Both of 174 and 219 significantly changed metabolites were identified in human SMMC-7721 cells treated with 20 and 50 µg/mL ZnO QDs, respectively. ZnO QDs significantly modified metabolic pathways, including purine metabolism, ferroptosis, morphine addiction, alcoholism, cGMP-PKG signaling, and Cushing syndrome. Moreover, we identified 105 and 8 differentially expressed proteins in cells treated with 20 and 50 µg/mL ZnO QDs, and the pathways of alcoholism and Cushing syndrome were enriched. Conclusion: ZnO QDs did not affect cell viability in a CCK8 assay, but disturbed the level of intracellular metabolites and proteins at 20 µg/mL. The KEGG analyses of the metabolomics and proteomics data both enriched the alcoholism and Cushing syndrome pathways. These results provide an experimental basis for future research on the safe use of nanomaterials.

Cushing's syndrome is associated with altered adipokine profile.

Introduction: Adipokines are signaling molecules involved in the integration of metabolism. Changes in their concentrations were observed in obesity, metabolic syndrome, diabetes mellitus and cardiovascular diseases, as well as endocrine disorders. Cushing's syndrome is associated with metabolic dysregulation, but the significance of adipokines in this entity and related complications is largely unknown. The aim of our study was to determine the concentrations of adipokines: fetuin A, fatty acid binding protein 4 (FABP4) and retinol binding protein 4 (RBP4) in Cushing's syndrome and to assess their relation to established cardiovascular and diabetes risk markers. Methods: We examined 21 subjects with Cushing's syndrome and 24 healthy controls in a cross-sectional manner. Venous blood samples were analysed for adipokines, cortisol, adrenocorticotrophin, glucose, insulin, glycated haemoglobin (HbA1c), triglycerides, cholesterol fractions, thyrotropin and free thyroid hormones concentrations. Patients' body mass index (BMI) was evaluated, homeostatic model assessment-insulin resistance and Systematic Coronary Risk Evaluation (SCORE) were calculated. Results: We found that the concentration of fetuin A was lower, while FABP4 and RBP4 concentrations were higher in Cushing's syndrome compared to controls [156.4 ± 60.0 µg/ml vs 260.7 ± 49.6 µg/ml; 79.8 (35.2-156.1) ng/ml vs 27.9 (17.1-36.7) ng/ml and 34 (30-37.7) mg/l vs 25.8 (23.6-27.7) mg/l, respectively]. Fetuin A correlated inversely, while FABP4 and RBP4 positively, with the concentrations of urinary free cortisol and adrenocorticotrophin. Fetuin A was positively related to LDL-cholesterol, and negatively to SCORE and HbA1c. FABP4 was associated positively with BMI, HbA1c and triglycerides, while RBP4 correlated positively with triglycerides and systolic blood pressure. Conclusions: Adipokines' concentrations change in hypercortisolism. Further research is needed to ascertain whether adipokines are involved in the development of metabolic complications accompanying Cushing's syndrome or secondarily reflect metabolic dysregulation.

Apoptosis Evaluation in Circulating CD34+-Enriched Hematopoietic Stem and Progenitor Cells in Patients with Abnormally Increased Production of Endogenous Glucocorticoids in Course of Cushing's Syndrome.

Abnormalities in hematological parameters of peripheral blood have been noted in patients with endogenous Cushing's Syndrome (CS) in the corticotropin (ACTH)-dependent and ACTH-independent forms. Nevertheless, the exact mechanism of glucocorticoids (GCs) action on human hematopoiesis is still not entirely clear. The aim of the study was to determine whether endogenous excessive production of GCs could affect apoptosis of CD34+ cells enriched in hematopoietic stem and progenitor cells (HSPCs) collected from the peripheral blood of newly diagnosed CS patients. Flow cytometry, Annexin-V enzyme-linked immunosorbent assay, TUNEL assay, real-time quantitative PCR, and microarray RNA/miRNA techniques were used to characterize CS patients' HSPCs. We found that the glucocorticoid receptor (GR) protein expression levels in CS were higher than in healthy controls. A complex analysis of apoptotic status of CS patients' HSPC cells showed that GCs significantly augmented apoptosis in peripheral blood-derived CD34+ cells and results obtained using different methods to detect early and late apoptosis in analyzed cell population were consistent. CS was also associated with significant upregulation in several members of the BCL-2 superfamily and other genes associated with apoptosis control. Furthermore, global gene expression analysis revealed significantly higher expression of genes associated with programmed cell death control in HSPCs from CS patients. These findings suggest that human endogenous GCs have a direct pro-apoptotic activity in hematopoietic CD34+ cells derived from CS subjects before treatment.

Glucose and lipid metabolism abnormalities in Cushing's syndrome.

Prolonged excess of glucocorticoids (GCs) has adverse systemic effects leading to significant morbidities and an increase in mortality. Metabolic alterations associated with the high level of the GCs are key risk factors for the poor outcome. These include GCs causing excess gluconeogenesis via upregulation of key enzymes in the liver, a reduction of insulin sensitivity in skeletal muscle, liver and adipose tissue by inhibiting the insulin receptor signalling pathway, and inhibition of insulin secretion in beta cells leading to dysregulated glucose metabolism. In addition, chronic GC exposure leads to an increase in visceral adipose tissue, as well as an increase in lipolysis resulting in higher circulating free fatty acid levels and in ectopic fat deposition. Remission of hypercortisolism improves these metabolic changes, but very often does not result in full resolution of the abnormalities. Therefore, long-term monitoring of metabolic variables is needed even after the resolution of the excess GC levels.

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.

New Insights into the Role of Insulin and Hypothalamic-Pituitary-Adrenal (HPA) Axis in the Metabolic Syndrome.

Recent data suggests that (pre)diabetes onset is preceded by a period of hyperinsulinemia. Consumption of the "modern" Western diet, over-nutrition, genetic background, decreased hepatic insulin clearance, and fetal/metabolic programming may increase insulin secretion, thereby causing chronic hyperinsulinemia. Hyperinsulinemia is an important etiological factor in the development of metabolic syndrome, type 2 diabetes, cardiovascular disease, polycystic ovarian syndrome, and Alzheimer's disease. Recent data suggests that the onset of prediabetes and diabetes are preceded by a variable period of hyperinsulinemia. Emerging data suggest that chromic hyperinsulinemia is also a driving force for increased activation of the hypothalamic-adrenal-pituitary (HPA) axis in subjects with the metabolic syndrome, leading to a state of "functional hypercortisolism". This "functional hypercortisolism" by antagonizing insulin actions may prevent hypoglycemia. It also disturbs energy balance by shifting energy fluxes away from muscles toward abdominal fat stores. Synergistic effects of hyperinsulinemia and "functional hypercortisolism" promote abdominal visceral obesity and insulin resistance which are core pathophysiological components of the metabolic syndrome. It is hypothesized that hyperinsulinemia-induced increased activation of the HPA axis plays an important etiological role in the development of the metabolic syndrome and its consequences. Numerous studies have demonstrated reversibility of hyperinsulinemia with lifestyle, surgical, and pharmaceutical-based therapies. Longitudinal studies should be performed to investigate whether strategies that reduce hyperinsulinemia at an early stage are successfully in preventing increased activation of the HPA axis and the metabolic syndrome.

ß-cell function and insulin sensitivity contributions on incident diabetes in patients with endogenous Cushing's syndrome.

OBJECTIVE: To evaluate the relative contributions of ß-cell function and insulin sensitivity on the deterioration of glucose tolerance from OGTT in patients with endogenous CS. METHODS: We retrospectively analyzed the data of 60 patients with CS and determined the glucose metabolism and ß-cell function through OGTT. Their general characteristics were retrieved. A series of parameters for assessing insulin sensitivity and ß-cell function was calculated. The logistic regression model was used to investigate insulin sensitivity and ß-cell function contributions on incident diabetes. RESULTS: Of the 60 patients with CS, 10 (16.7%), 21 (35%), and 29 (48.3%) were classified as CS/ normal glucose tolerance (NGT), CS/prediabetes, and CS/diabetes mellitus (DM). Compared with the HCs, the CS/NGT patients had higher HOMA-IR and lower ISI-Matsuda but with a compensatory increase in HOMA-ß. Significant decreasing trends were observed in HOMA-ß, AUCI/G and ΔI30/ΔG30 among CS/NGT, CS/prediabetes and CD/DM groups. The OR of incident diabetes compared with the high AUCI/G/high ISI group was significant in the low AUCI/G/high ISI group. CONCLUSION: Impairment of the ß-cell function had a more profound effect on incident diabetes than decreased insulin sensitivity. An approach based on an OGTT has utility for diagnosing dysglycaemia and ß-cell dysfunction in patients with CS.

Mislocalization of protein kinase A drives pathology in Cushing's syndrome.

Mutations in the catalytic subunit of protein kinase A (PKAc) drive the stress hormone disorder adrenal Cushing's syndrome. We define mechanisms of action for the PKAc-L205R and W196R variants. Proximity proteomic techniques demonstrate that both Cushing's mutants are excluded from A kinase-anchoring protein (AKAP)-signaling islands, whereas live-cell photoactivation microscopy reveals that these kinase mutants indiscriminately diffuse throughout the cell. Only cAMP analog drugs that displace native PKAc from AKAPs enhance cortisol release. Rescue experiments that incorporate PKAc mutants into AKAP complexes abolish cortisol overproduction, indicating that kinase anchoring restores normal endocrine function. Analyses of adrenal-specific PKAc-W196R knockin mice and Cushing's syndrome patient tissue reveal defective signaling mechanisms of the disease. Surprisingly each Cushing's mutant engages a different mitogenic-signaling pathway, with upregulation of YAP/TAZ by PKAc-L205R and ERK kinase activation by PKAc-W196R. Thus, aberrant spatiotemporal regulation of each Cushing's variant promotes the transmission of distinct downstream pathogenic signals.

Whom Should We Screen for Cushing Syndrome? The Endocrine Society Practice Guideline Recommendations 2008 Revisited.

CONTEXT: Cushing syndrome (CS) is a rare and serious disease with high mortality. Patients are often diagnosed late in the course of the disease. OBJECTIVE: This work investigated whether defined patient populations should be screened outside the at-risk populations defined in current guidelines. METHODS: As part of the prospective German Cushing registry, we studied 377 patients with suspected CS. The chief complaint for CS referral was documented. Using urinary free cortisol, late-night salivary cortisol, and the 1-mg dexamethasone suppression test as well as long-term clinical observation, CS was confirmed in 93 patients and ruled out for the remaining 284. RESULTS: Patients were referred for 18 key symptoms, of which 5 were more common in patients with CS than in those in whom CS was ruled out: osteoporosis (8% vs 2%; P = .02), adrenal incidentaloma (17% vs 8%, P = 0.01), metabolic syndrome (11% vs 4%; P = .02), myopathy (10% vs 2%; P < .001), and presence of multiple symptoms (16% vs 1%; P < .001). Obesity was more common in patients in whom CS was ruled out (30% vs 4%, P < .001), but recent weight gain was prominent in those with CS. A total of 68 of 93 patients with CS (73%) had typical chief complaints, as did 106 of 284 of patients with ruled-out CS status (37%) according to the Endocrine Society practice guideline 2008. CONCLUSION: The 2008 Endocrine Society Practice guideline for screening and diagnosis of CS defined at-risk populations that should undergo testing. These recommendations are still valid in 2022.

Gene expression changes in the brain of a Cushing's syndrome mouse model.

Excess glucocorticoid exposure affects emotional and cognitive brain functions. The extreme form, Cushing's syndrome, is adequately modelled in the AdKO2.0 mouse, consequential to adrenocortical hypertrophy and hypercorticosteronemia. We previously reported that the AdKO2.0 mouse brain undergoes volumetric changes that resemble closely those of Cushing's syndrome human patients, as well as changes in expression of glial related marker proteins. In the present work, the expression of genes related to glial and neuronal cell populations and functions was assessed in regions of the anterior brain, hippocampus, amygdala and hypothalamus. Glucocorticoid target genes were consistently regulated, including CRH mRNA suppression in the hypothalamus and induction in amygdala and hippocampus, even if glucocorticoid receptor protein was downregulated. Expression of glial genes was also affected in the AdKO2.0 mouse brain, indicating a different activation status in glial cells. Generic markers for neuronal cell populations, and cellular integrity were only slightly affected. Our findings highlight the vulnerability of glial cell populations to chronic high levels of circulating glucocorticoids.

The Association of Cholesterol Uptake and Synthesis with Histology and Genotype in Cortisol-Producing Adenoma (CPA).

Cortisol-producing adenoma (CPA) is composed of clear and compact cells. Clear cells are lipid abundant, and compact ones lipid poor but associated with higher production of steroid hormones. PRKACA mutation (PRKACA mt) in CPA patients was reported to be associated with more pronounced clinical manifestation of Cushing's syndrome. In this study, we examined the association of histological features and genotypes with cholesterol uptake receptors and synthetic enzymes in 40 CPA cases, and with the quantitative results obtained by gas chromatography-mass spectrometry (GC-MS) analysis in 33 cases to explore their biological and clinical significance. Both cholesterol uptake receptors and synthetic enzymes were more abundant in compact cells. GC-MS analysis demonstrated that the percentage of compact cells was inversely correlated with the concentrations of cholesterol and cholesterol esters, and positively with the activity of cholesterol biosynthesis from cholesterol esters. In addition, hormone-sensitive lipase (HSL), which catalyzes cholesterol biosynthesis from cholesterol esters, tended to be more abundant in compact cells of PRKACA mt CPAs. These results demonstrated that both cholesterol uptake and biosynthesis were more pronounced in compact cells in CPA. In addition, more pronounced HSL expression in compact cells of PRKACA mt CPA could contribute to their more pronounced clinical manifestation.

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.