The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review.

Aims: Primary pigmented nodular adrenocortical disease (PPNAD), as a rare kind of Cushing's syndrome, is frequently misdiagnosed. To get a better understanding of the disease, we analyzed the clinical characteristics and pathogenic variants of PPNAD. Methods: Databases were searched, and the pathogenic variants and clinical manifestations of patients were summarized from the relevant articles. Results: A total of 210 patients in 86 articles were enrolled with a median age of 22 and a female-to-male ratio of 2:1. Sixty-six (31.43%) patients were combined with Carney complex (CNC) and 94.29% were combined with osteoporosis/osteopenia. Among 151 patients who underwent genetic testing, 87.42% (132/151) had pathogenic variants. Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients. The most common mutation was PKAR1A, accounting for 79.47% (120/151). There was a significant correlation between PRKAR1A pathogenic variant and spotty skin pigmentation in CNC concurrent with PPNAD (p < 0.05). Among pregnant patients with PPNAD, those without surgical treatment and with bilateral adrenalectomy suffered from a high-risk perinatal period. However, patients with unilateral adrenalectomy presented a safe perinatal period. Conclusions: For young patients with Cushing's syndrome, especially female patients with spotty skin pigmentation and osteoporosis/osteopenia, PPNAD should be considered. Unilateral adrenal resection may be considered as an option for women with fertility needs. In view of the difficulty of PPNAD diagnosis, genetic testing before surgery might be a reasonable option. Patients with PPNAD with spotty skin pigmentation should consider the PRKAR1A pathogenic variant and pay attention to CNC. Systematic review registration: https://www.crd.york.ac.uk/prospero, identifier CRD42023416988.

Novel PRKAR1A mutation in Carney complex: a case report and literature review.

Objective: Carney complex is a rare autosomal dominant syndrome that has been shown to be associated with inactivation due to PRKAR1A mutations. We revealed a novel PRKAR1A gene mutation in Chinese patient with Carney complex and review the literature to enhance understanding of Carney complex. Case presentation: A 23-year-old Chinese male patient with a family history cardiac myxoma was admitted to our Department of Endocrinology because of central obesity and hyperpigmentation. Physical examination revealed a maximum blood pressure of 150/93mmHg, a waist circumference of 102cm, a weight of 70kg, a height of 170cm, and a BMI of 24.22kg/m2. Additionally, there was spotty skin pigmentation on the lip mucosa, purple striae on the abdomen, thin skin on both legs, and visible veins. Blood examination revealed hypercortisolemia, decreased adrenocorticotropic hormone (ACTH) levels and failure to suppress cortisol with low and high-dose dexamethasone suppression tests. Magnetic resonance imaging (MRI) scan revealed multiple small adrenal nodules and Retroperitoneal neurogenic tumor. Genetic testing showed a novel heterozygous mutation in exon 5 of PRKAR1A (c.500_502 + 8delAAGGTAAGGGC). The patient underwent resection of the right adrenal gland and retroperitoneal neoplasms in 2020. Postoperative pathology following the right adrenal gland resection showed nodular hyperplasia of the adrenal cortex. The pathology from the retroperitoneal tumor resection revealed spindle cell tumors rich in pigment and cells. The patient was diagnosed as Carney complex according to Stratakis CA in 2001 guidelines. After long-term follow-up, the patient's condition was stable, with weight loss, waist circumference reduction, significantly lower cortisol levels, and normal blood lipids. Conclusion: This case reported a Carney complex in a Chinese patient, characterized clinically by non-ACTH-dependent Cushing's syndrome, familial recurrent cardiac myxomas, psammomatous melanotic schwannoma (PMS) and skin and mucosal pigmentation. A novel subtype of PRKAR1A mutation was discovered, which may affect the characteristics of the PRKAR1A protein and contribute to the development of Carney complex.

Simulations of a PKA RIα homodimer reveal cAMP-coupled conformational dynamics of each protomer and the dimer interface with functional implications.

Protein kinase A (PKA) is a ubiquitous cAMP-dependent enzyme in mammalian tissues. The inactive PKA holoenzyme disassociates into a homodimer of regulatory (R) subunits and two active catalytic (C) subunits upon cAMP binding to two tandem domains (termed CBD-A and CBD-B) in R subunits. The release of cAMP facilitates reassociation of R and C subunits, resetting PKA to its basal state. The cAMP-mediated structural changes in the activation-termination cycle remain partially understood. The multimeric states of PKA complicate the issue and are particularly less studied. Therefore, we computationally investigated the conformational dynamics of the PKA RIα homodimer in different cAMP-bound states. The absence of cAMP in two CBDs differently affects the conformational dynamics of protomers. Moreover, such disparate responses are extended to the dimer interface constituted by the N-terminal helical sub-domains termed N3A motifs. The removal of cAMP from CBD-A induces large-scale structural changes of individual R subunits towards the holoenzyme state, consistent with previous simulations of a single R subunit. Meanwhile it keeps the structural heterogeneity of the N3A-N3A' dimer interface observed in the fully bound state. By contrast, the removal of cAMP from CBD-B does not affect individual R subunits but alters the conformational space of the N3A-N3A' dimer interface. The cAMP-coupled structural changes of each protomer and conserved conformational space of the N3A-N3A' dimer interface are essential for the transition between the fully cAMP-bound R2 homodimer and the R2C2 holoenzyme as suggested by their crystal structures. Our work provides structural insights into the regulatory mechanism of cAMP in PKA signaling.

Diagnosis and cardiac transplantation of a Carney syndrome-induced cardiac myxoma combined with dilated cardiomyopathy: a case report.

BACKGROUND: Carney syndrome is an uncommon autosomal disorder closely linked to mutations in the PRKAR1A gene. Skin lesions are the most pronounced feature of Carney syndrome, affecting over 80% of individuals with this condition. This syndrome is characterized by a triad of myxomas, skin pigmentation, and endocrine hyperfunction, featuring multiple endocrine neoplasms with skin and cardiac involvement. Dilated cardiomyopathy, a primary cardiomyopathy, is defined as the dilation and impaired systolic function of the left or both ventricles. Its clinical presentation varies from being asymptomatic to heart failure or sudden cardiac death, making it a leading global cause of heart failure. Currently, Dilated cardiomyopathy has an estimated prevalence of 1/2500-1/250 individuals, predominantly affecting those aged 30-40 years, with a male-to-female ratio of 3:1. This case report describes a heart failure patient with cardiac myxoma caused by Carney syndrome combined with dilated cardiomyopathy. The patient was successfully treated for heart failure by heart transplantation. CASE PRESENTATION: Herein, we report a case of heart failure due to Carney syndrome that resulted in cardiac myxoma combined with dilated cardiomyopathy. A 35-year-old male was admitted to the hospital three years ago because of sudden chest tightness and shortness of breath. Echocardiography indicated myxoma, and a combination of genetic screening and physical examination confirmed Carney syndrome with cardiac myxoma. Following symptomatic management, he was discharged. Surgical interventions were not considered at the time. However, the patient's chest tightness and shortness of breath symptoms worsened, and he returned to the hospital. A New York Heart Association grade IV heart function was confirmed, and echocardiography indicated the presence of dilated cardiomyopathy accompanied by cardiac myxoma. Ultimately, the patient's heart failure was successfully treated with heart transplantation. CONCLUSIONS: Cardiac myxoma caused by Carney syndrome combined with heart failure caused by dilated cardiomyopathy can be resolved by heart transplantation.

Bilateral Adrenocortical Nodular Disease and Cushing's Syndrome.

Primary pigmented nodular adrenocortical disease (PPNAD) and bilateral macronodular adrenocortical disease (BMAD) are 2 forms of adrenocortical nodular diseases causing Cushing's syndrome but are 2 very distinct conditions. PPNAD, affecting mostly young patients with an almost constant severe Cushing's syndrome, is characterized by pigmented micronodules, usually less than 1 cm, not always visible on imaging. On the contrary, BMAD is predominantly diagnosed in the fifth and sixth decades, with highly variable degrees of cortisol excess, from mild autonomous cortisol secretion to overt Cushing's syndrome. BMAD presents as large bilateral adrenal macronodules, easily observed on imaging. Both diseases are often genetically determined: frequently PPNAD is observed in a multiple neoplasia syndrome, Carney complex, and a germline genetic defect is identified in around 80% of index cases, always affecting key actors of the cAMP/protein kinase A (PKA) pathway: mostly PRKAR1A, encoding the PKA 1-alpha regulatory subunit. On the other hand, BMAD appears mostly isolated, and 2 predisposing genes are known at present: ARMC5, accounting for around 20% of index cases, and the recently identified KDM1A, causing the rare presentation with food-dependent Cushing's syndrome, mediated by the ectopic expression of the glucose-dependent insulinotropic polypeptide receptor (GIPR) in adrenal nodules. GIPR was the first demonstrated receptor to illegitimately regulate cortisol secretion in nodular adrenocortical diseases, and a myriad of other receptors and paracrine signals were discovered afterward. The last 30 years were pivotal in the understanding of the genetics and pathophysiology of bilateral adrenocortical nodular diseases, leading to a personalized approach of these fascinating conditions.

Frequent protein kinase A regulatory subunit A1 mutations but no GNAS mutations as potential driver in sporadic cardiac myxomas.

PURPOSE: Cardiac myxomas (CMs) are the second most common benign primary cardiac tumors, mainly originating within the left atrium. Approximately 5% of CM cases are associated with Carney Complex (CNC), an autosomal dominant multiple neoplasia syndrome often caused by germline mutations in the protein kinase A regulatory subunit 1A (PRKAR1A). Data concerning PRKAR1A alterations in sporadic myxomas are variable and sparse, with PRKAR1A mutations reported to range from 0% to 87%. Therefore, we investigated the frequency of PRKAR1A mutations in sporadic CM using next-generation sequencing (NGS). Additionally, we explored mutations in the catalytic domain of the Protein Kinase A complex (PRKACA) and examined the presence of GNAS mutations as another potential driver. METHODS AND RESULTS: This study retrospectively collected histological and clinical data from 27 patients with CM. First, we ruled out the possibility of underlying CNC through clinical evaluations and standardized interviews for each patient. Second, we performed PRKAR1A immunohistochemistry (IHC) analysis and graded the reactivity of myxoma cells semi-quantitatively. NGS was then applied to analyze the coding regions of PRKAR1A, PRKACA, and GNAS in all 27 cases. Of the 27 sporadic CM cases, 13 (48%) harbored mutations in PRKAR1A. Among these 13 mutant cases, six displayed more than one mutation in PRKAR1A. Most of the identified mutations resulted in premature stop codons or affected splicing. In PRKAR1A mutant CM cases, the loss of PRKAR1A protein expression was significantly more common. In two cases with missense mutations, protein expression remained preserved. Furthermore, a single mutation was detected in the catalytic domain of the protein kinase A complex, while no GNAS mutations were found. CONCLUSION: We identified a relatively high frequency of PRKAR1A mutations in sporadic CM. These PRKAR1A mutations may also represent an important oncogenic mechanism in sporadic myxomas, as already known in CM cases associated with CNC.

Molecular determinants and signaling effects of PKA RIα phase separation.

Spatiotemporal regulation of intracellular signaling molecules, such as the 3',5'-cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA), ensures proper cellular function. Liquid-liquid phase separation (LLPS) of the ubiquitous PKA regulatory subunit RIα promotes cAMP compartmentation and signaling specificity. However, the molecular determinants of RIα LLPS remain unclear. Here, we reveal that two separate dimerization interfaces, combined with the cAMP-induced unleashing of the PKA catalytic subunit (PKA-C) from the pseudosubstrate inhibitory sequence, drive RIα condensate formation in the cytosol of mammalian cells, which is antagonized by docking to A-kinase anchoring proteins. Strikingly, we find that the RIα pseudosubstrate region is critically involved in forming a non-canonical R:C complex, which recruits active PKA-C to RIα condensates to maintain low basal PKA activity in the cytosol. Our results suggest that RIα LLPS not only facilitates cAMP compartmentation but also spatially restrains active PKA-C, thus highlighting the functional versatility of biomolecular condensates in driving signaling specificity.

Dualistic Effects of PRKAR1A as a Potential Anticancer Target in Cancer Cells and Cancer-Derived Stem Cells.

The integration of innovative medical technologies and interdisciplinary collaboration could improve the treatment of cancer, a globally prevalent and often deadly disease. Despite recent advancements, current cancer therapies fail to specifically address recurrence and target cancer stem cells (CSCs), which contribute to relapse. In this study, we utilized three types of cancer cells, from which three types of CSCs were further derived, to conduct a proteomic analysis. Additionally, shared cell surface biomarkers were identified as potential targets for a comprehensive treatment strategy. The selected biomarkers were evaluated through short hairpin RNA treatment, which revealed contrasting functions in cancer cells and CSCs. Knockdown of the identified proteins revealed that they regulate the epithelial-mesenchymal transition (EMT) and stemness via the ERK signaling pathway. Resistance to anticancer agents was consequently reduced, ultimately enhancing the overall anticancer effects of the treatment. Additionally, the significance of these biomarkers in clinical patient outcomes was confirmed using bioinformatics. Our study suggests a novel cancer treatment strategy that addresses the limitations of current anticancer therapies.

14-3-3 interaction with phosphodiesterase 8A sustains PKA signaling and downregulates the MAPK pathway.

The cAMP/PKA and mitogen-activated protein kinase (MAPK) signaling cascade control many cellular processes and are highly regulated for optimal cellular responses upon external stimuli. Phosphodiesterase 8A (PDE8A) is an important regulator that inhibits signaling via cAMP-dependent PKA by hydrolyzing intracellular cAMP pool. Conversely, PDE8A activates the MAPK pathway by protecting CRAF/Raf1 kinase from PKA-mediated inhibitory phosphorylation at Ser259 residue, a binding site of scaffold protein 14-3-3. It still remains enigmatic as to how the cross-talk involving PDE8A regulation influences cAMP/PKA and MAPK signaling pathways. Here, we report that PDE8A interacts with 14-3-3ζ in both yeast and mammalian system, and this interaction is enhanced upon the activation of PKA, which phosphorylates PDE8A's Ser359 residue. Biophysical characterization of phospho-Ser359 peptide with 14-3-3ζ protein further supports their interaction. Strikingly, 14-3-3ζ reduces the catalytic activity of PDE8A, which upregulates the cAMP/PKA pathway while the MAPK pathway is downregulated. Moreover, 14-3-3ζ in complex with PDE8A and cAMP-bound regulatory subunit of PKA, RIα, delays the deactivation of PKA signaling. Our results define 14-3-3ζ as a molecular switch that operates signaling between cAMP/PKA and MAPK by associating with PDE8A.

Carney complex predisposes to breast cancer: prospective study of 50 women.

OBJECTIVE: Carney complex (CNC) is a rare genetic syndrome, mostly due to germline loss-of-function pathogenic variants in PRKAR1A. Carney complex includes pigmented skin lesions, cardiac myxomas, primary pigmented nodular adrenocortical dysplasia, and various breast benign tumors. DESIGN: The present study was designed to describe the characteristics of breast lesions in CNC patients and their association with other manifestations of CNC and PRKAR1A genotype. METHODS: A 3-year follow-up multicenter French prospective study of CNC patients included 50 women who were analyzed for CNC manifestations and particularly breast lesions, with breast imaging, genotyping, and hormonal settings. RESULTS: Among the 38 women with breast imaging, 14 (39%) had breast lesions, half of them bilateral. Ten women (26%) presented with benign lesions and six with breast carcinomas (16%): one had ductal carcinoma in situ at 54, and five had invasive cancer before 50 years old, whom one with contralateral breast cancer during follow-up. The occurrence of breast cancer was more frequent in women with PRKAR1A pathogenic variant odds ratio = 6.34 (1.63-17.91) than in general population of same age. The mean age at breast cancer diagnosis was 44.7 years old: 17 years younger than in the general population. Breast cancer patients had good prognosis factors. All breast carcinomas occurred in individuals with familial CNC and PRKAR1A pathogenic variants. Loss of heterozygosity at the PRKAR1A locus in the 2 invasive breast carcinomas analyzed suggested a driver role of this tumor suppressor gene. CONCLUSIONS: As CNC could predispose to breast carcinoma, an adequate screening strategy and follow-up should be discussed in affected women. CLINICAL TRIAL REGISTRATION: ClinicalTrial.gov NCT00668291.