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Celso E Gomezsanchez - One of the best experts on this subject based on the ideXlab platform.
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primary aldosteronism KCNJ5 mutations and adrenocortical cell growth
Hypertension, 2019Co-Authors: Yuhong Yang, Felix Beuschlein, Celso E Gomezsanchez, Diana Jaquin, Elke Tatjana Aristizabal Prada, Lucie S Meyer, Thomas Knosel, Holger Schneider, Martin ReinckeAbstract:Aldosterone-producing adenomas with somatic mutations in the KCNJ5 G-protein-coupled inwardly rectifying potassium channel are a cause of primary aldosteronism. These mutations drive aldosterone excess, but their role in cell growth is undefined. Our objective was to determine the role of KCNJ5 mutations in adrenal cell proliferation and apoptosis. The Ki67 proliferative index was positively correlated with adenoma diameter in aldosterone-producing adenomas with a KCNJ5 mutation (r=0.435, P=0.007), a negative correlation was noted in adenomas with no mutation detected (r=-0.548, P=0.023). Human adrenocortical cell lines were established with stable expression of cumate-inducible wild-type or mutated KCNJ5. Increased cell proliferation was induced by low-level induction of KCNJ5-T158A expression compared with control cells (P=0.009), but increased induction ablated this difference. KCNJ5-G151R displayed no apparent proliferative effect, but KCNJ5-G151E and L168R mutations each resulted in decreased cell proliferation (difference P<0.0001 from control cells, both comparisons). Under conditions tested, T158A had no effect on apoptosis, but apoptosis increased with expression of G151R (P<0.0001), G151E (P=0.008), and L168R (P<0.0001). We generated a specific KCNJ5 monoclonal antibody which was used in immunohistochemistry to demonstrate strong KCNJ5 expression in adenomas without a KCNJ5 mutation and in the zona glomerulosa adjacent to adenomas irrespective of genotype as well as in aldosterone-producing cell clusters. Double immunofluorescence staining for KCNJ5 and CYP11B2 (aldosterone synthase) showed markedly decreased KCNJ5 immunostaining in CYP11B2-positive cells compared with CYP11B2-negative cells in aldosterone-producing adenomas with a KCNJ5 mutation. Together, these findings support the concept that cell growth effects of KCNJ5 mutations are determined by the expression level of the mutated channel.
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tumor cell subtypes based on the intracellular hormonal activity in KCNJ5 mutated aldosterone producing adenoma
Hypertension, 2018Co-Authors: Yuto Yamazaki, Kei Omata, Yuta Tezuka, Yoshikiyo Ono, Ryo Morimoto, Yuzu Adachi, Kazue Ise, Yasuhiro Nakamura, Celso E GomezsanchezAbstract:Aldosterone-producing adenomas (APAs) harbor marked intratumoral heterogeneity in terms of morphology, steroidogenesis, and genetics. However, an association of biological significance of morphologically identified tumor cell subtypes and genotypes is virtually unknown. KCNJ5 mutation is most frequently detected and generally considered a curable phenotype by adrenalectomy. Therefore, to explore the biological significance of KCNJ5 mutation in APA based on intracellular hormonal activities, 35 consecutively selected APAs (n=18; KCNJ5 mutated, n=17; wild type) were quantitatively examined in the whole tumor areas by newly developed digital image analysis incorporating their histological and ultrastructural features (14 cells from 2 KCNJ5-mutated APAs and 15 cells from 1 wild type) and CYP11B2 immunoreactivity. Results demonstrated that KCNJ5-mutated APAs had significantly lower nuclear/cytoplasm ratio and more abundant clear cells than wild type. CYP11B2 immunoreactivity was not significantly different between these genotypes, but a significant correlation was detected between the proportion of clear cells and CYP11B2 immunoreactivity in all of the APAs examined. CYP11B2 was predominantly immunolocalized in clear cells in KCNJ5-mutated APAs. Quantitative ultrastructural analysis revealed that KCNJ5-mutated APAs had significantly more abundant and smaller-sized mitochondria with well-developed cristae than wild type, whereas wild type had more abundant lipid droplets per unit area despite the small number of the cases examined. Our results did provide the novel insights into the morphological features of APA based on their biological significance. KCNJ5-mutated APAs were characterized by predominance of enlarged lipid-rich clear cells possibly resulting in increased neoplastic aldosterone biosynthesis.
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disordered zonal and cellular cyp11b2 enzyme expression in familial hyperaldosteronism type 3
Molecular and Cellular Endocrinology, 2017Co-Authors: Hironobu Sasano, Celso E Gomezsanchez, Elise P Gomezsanchez, Martin O Bohlen, Max WisgerhofAbstract:Three forms of familial primary aldosteronism have been recognized. Familial Hyperaldosteronism type 1 (FH1) or dexamethasone suppressible hyperaldosteronism, FH2, the most common form of as yet unknown cause(s), and FH3. FH3 is due to activating mutations of the potassium channel gene KCNJ5 that increase constitutive and angiotensin II-induced aldosterone synthesis. In this study we examined the cellular distribution of CYP11B2, CYP11B1, CYP17A1 and KCNJ5 in adrenals from two FH3 siblings using immunohistochemistry and immunofluorescence and obtained unexpected results. The adrenals were markedly enlarged with loss of zonation. CYP11B2 was expressed sporadically throughout the adrenal cortex. CYP11B2 was most often expressed by itself, relatively frequently with CYP17A1, and less frequently with CYP11B1. KCNJ5 was co-expressed with CYP11B2 and in some cells with CYP11B1. This aberrant co-expression of enzymes likely explains the abnormally high secretion rate of the hybrid steroid, 18-oxocortisol.
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mutated KCNJ5 activates the acute and chronic regulatory steps in aldosterone production
Journal of Molecular Endocrinology, 2016Co-Authors: Namita G Hattangady, William E Rainey, Celso E Gomezsanchez, Shigehiro Karashima, Lucy Yuan, Daniela Poncebalbuena, Jose Jalife, Richard J Auchus, Tobias ElseAbstract:Somatic and germline mutations in the inward-rectifying K(+) channel (KCNJ5) are a common cause of primary aldosteronism (PA) in aldosterone-producing adenoma and familial hyperaldosteronism type III, respectively. Dysregulation of adrenal cell calcium signaling represents one mechanism for mutated KCNJ5 stimulation of aldosterone synthase (CYP11B2) expression and aldosterone production. However, the mechanisms stimulating acute and chronic production of aldosterone by mutant KCNJ5 have not been fully characterized. Herein, we defined the effects of the T158A KCNJ5 mutation (KCNJ5(T158A)) on acute and chronic regulation of aldosterone production using an adrenal cell line with a doxycycline-inducible KCNJ5(T158A) gene (HAC15-TRE-KCNJ5(T158A)). Doxycycline incubation caused a time-dependent increase in KCNJ5(T158A) and CYP11B2 mRNA and protein levels. Electrophysiological analyses confirm the loss of inward rectification and increased Na(+) permeability in KCNJ5(T158A)-expressing cells. KCNJ5(T158A) expression also led to the activation of CYP11B2 transcriptional regulators, NURR1 and ATF2. Acutely, KCNJ5(T158A) stimulated the expression of total and phosphorylated steroidogenic acute regulatory protein (StAR). KCNJ5(T158A) expression increased the synthesis of aldosterone and the hybrid steroids 18-hydroxycortisol and 18-oxocortisol, measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS). All of these stimulatory effects of KCNJ5(T158A) were inhibited by the L-type Ca(2+) channel blocker, verapamil. Overall, KCNJ5(T158A)increases CYP11B2 expression and production of aldosterone, corticosterone and hybrid steroids by upregulating both acute and chronic regulatory events in aldosterone production, and verapamil blocks KCNJ5(T158A)-mediated pathways leading to aldosterone production.
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regulation of aldosterone biosynthesis by the kir3 4 KCNJ5 potassium channel
Clinical and Experimental Pharmacology and Physiology, 2013Co-Authors: Carolina Velardemiranda, Elise P Gomezsanchez, Celso E GomezsanchezAbstract:The G-protein-activated inwardly rectifying potassium channel Kir3.4 is expressed in the zona glomerulosa cell membrane and transports potassium out of the cell. Angiotensin II stimulation of aldosterone secretion is mediated, in part, by suppression of the transcription of KCNJ5, the gene coding for Kir3.4, and blocking channel activity. This results in membrane depolarization, mobilization of intracellular calcium, activation of the calcium-calmodulin pathway and increasing gene transcription of steroidogenic enzymes required for aldosterone secretion. In 40-60% of aldosterone-producing adenomas there is a somatic mutation in the region of the KCNJ5 gene that codes for the selectivity filter that decreases potassium selectivity, allowing sodium to leak into the cells, thus depolarizing the membrane and initiating events that result in increased aldosterone synthesis. The mechanism by which mutated KCNJ5 induces cell proliferation and adenoma formation remains unclear.
Gian Paolo Rossi - One of the best experts on this subject based on the ideXlab platform.
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macrolides for KCNJ5 mutated aldosterone producing adenoma mapa design of a study for personalized diagnosis of primary aldosteronism
Blood Pressure, 2018Co-Authors: Giuseppe Maiolino, Maurizio Cesari, Laurence Amar, Michel Azizi, Michele Battistel, Giulio Barbiero, Roberto Padrini, Giulio Ceolotto, Brasilina Caroccia, Gian Paolo RossiAbstract:AbstractPurpose: Aldosterone-producing adenoma (APA) is the main curable cause of endocrine hypertension cause of primary aldosteronism (PA) and it is in up to 66% of all cases investigated with adrenal vein sampling (AVS). Mutations in the KCNJ5 potassium channel involve up to 70% of APA and cause the most florid PA phenotypes. The recent finding that macrolide antibiotics specifically inhibit in vitro the altered function of mutated KCNJ5 channels has opened new horizons for the diagnosis and treatment of APA with KCNJ5 mutations in that it can allow identification and target treatment of PA patients harbouring a mutated APA. Thus, we aimed at investigating if clarithromycin and roxithromycin, two macrolides that potently blunt mutated Kir3.4 channel function in vitro, affect plasma aldosterone concentration in adrenal vein blood during AVS and in peripheral blood, respectively, in PA patients with a mutated APA.Methods and design: We designed two proof of concept studies. In study A: consecutive patien...
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macrolides blunt aldosterone biosynthesis a proof of concept study in KCNJ5 mutated adenoma cells ex vivo
Hypertension, 2017Co-Authors: Brasilina Caroccia, Giuseppe Maiolino, Selene Prisco, Teresa Maria Seccia, Maria Piazza, Gian Paolo RossiAbstract:Aldosterone-producing adenoma (APA), a major subtype of primary hyperaldosteronism, the main curable cause of human endocrine hypertension, involves somatic mutations in the potassium channel Kir3.4 (KCNJ5) in 30% to 70% of cases, typically the more florid phenotypes. Because KCNJ5 mutated channels were reported to be specifically sensitive to inhibition by macrolide antibiotics, which concentration dependently blunts aldosterone production in HAC15 transfected with the G151R and L168R mutated channel, we herein tested the effect of clarithromycin on aldosterone synthesis and secretion in a pure population of aldosterone-secreting cells obtained by immunoseparation (CD56+ cells) from APA tissues with/without the 2 most common KCNJ5 mutations. From a large cohort of patients with an unambiguous APA diagnosis, we recruited those who were wild type (n=3) or had G151R (n=2) and L168R (n=2) mutations. We found that clarithromycin concentration dependently lowered CYP11B2 gene expression (by 60%) and aldosterone secretion (by 70%; P<0.001 for both) in CD56+ cells isolated ex vivo from KCNJ5 mutated APAs, although it was ineffective in CD56+ cells from wild-type APAs. By proving the principle that the oversecretion of aldosterone can be specifically blunted in APA cells ex vivo with G151R and L168R mutations, these results provide compelling evidence of the possibility of specifically correcting aldosterone excess in patients with APA carrying the 2 most common KCNJ5 somatic mutations.
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abstract p212 a meta analysis of somatic KCNJ5 mutations in 1636 primary aldosteronism patients
Hypertension, 2015Co-Authors: Gian Paolo Rossi, Giuseppe Maiolino, Livia Lenzini, Giacomo Rossitto, C Letizia, John W FunderAbstract:Background: We meta-analysed the available studies reporting on KCNJ5 mutations in Aldosterone Producing Adenoma (APA) to determine the clinical characteristics of APA patients with a mutation of the KCNJ5 gene. Methods: We applied the PICO strategy using predefined terms (Population: primary aldosteronism patients with aldosterone producing adenoma; Intervention: adrenalectomy, sequencing for KCNJ5 mutations; Control: APA without KCNJ5 mutations; Outcome: clinical and pathological correlates of KCNJ5 mutations) to extract relevant studies from the PubMed, Scopus, Web of Science e Cochrane databases until January 2015. To allow for independent replication of the results, we elected to use the commercially available software. Results and Conclusions: By this PICO strategy we could identify 13 studies involving a total of 1636 patients (age 49 years ± 4; 55% females). The overall prevalence of KCNJ5 mutations was 43%; it was lower frequency (p Therefore, the meta-analysis of a large dataset comprising all studies available thus far showed that features associated with the presence of KCNJ5 mutations in PA due to APA entail young age, female gender, bigger tumor size and more prominent hyperaldosteronism.
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a meta analysis of somatic KCNJ5 k channel mutations in 1636 patients with an aldosterone producing adenoma
The Journal of Clinical Endocrinology and Metabolism, 2015Co-Authors: Livia Lenzini, Giuseppe Maiolino, Giacomo Rossitto, C Letizia, John W Funder, Gian Paolo RossiAbstract:Context: Due to selection biases and inadequate statistical power, individual studies may fail to identify the clinical features of patients with an aldosterone-producing adenoma (APA) harboring KCNJ5 mutations. When this failure occurs, meta-analysis can provide significant outcome data. Objective: The objective was to determine the clinical features of these APA patients. Design: We systematically searched the PubMed, Scopus, Web of Science, and Cochrane databases library in January 2015 applying the Population, Intervention, Comparison, and Outcome (PICO) strategy. The standardized differences in mean and corresponding 95% confidence interval of continuous variables were computed by random-effects modeling. Setting: We performed a meta-analysis of all available studies on somatic KCNJ5 mutations in APA. Patients: We could identify 13 studies that recruited 1636 patients (age 49 ± 4 years; 55% females). Main Outcomes and Measures: Differences between APA with and without KCNJ5 mutations in gender, plasm...
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abstract 011 identification and electrophysiological characterization of a novel somatic mutation inst149KCNJ5 of the potassium channel kir3 4 KCNJ5
Hypertension, 2014Co-Authors: Gian Paolo Rossi, Maniselvan Kuppusamy, Brasilina Caroccia, Julia Stindl, Sascha Bandulik, Livia Lenzini, Francesca Gioco, Michael Bader, Veniamin S Fishman, Giuseppe ZanottiAbstract:Context: Understanding the function of the Kir3.4 (KCNJ5 gene) potassium channel through characterization of occurring novel mutations is key for dissecting the mechanism(s) of autonomous aldosterone secretion in primary aldosteronism. Objective: To identify novel KCNJ5 channel mutations and functionally characterize them in a large database of patients with aldosterone-producing adenomas (APA). Methods: We sequenced the APA and germinal DNA of 195 consecutive patients, diagnosed with the four corners criteria of the PAPY study. Among the 24.6% (48/195) APA patients who showed somatic KCNJ5 mutations we discovered a novel c.446insAAC insertion resulting in the mutant protein KCNJ5-insT149 in a patient with severe drug-resistant hypertension. The mutated cDNA generated by site-directed mutagenesis was transfected along with KCNJ3 cDNA in mammalian cells. 17α-hydroxylase, CYP11B1, and CYP11B2 were immunochemically localized in the excised adrenal gland. Whole-cell patch clamp recordings, CYP11B2 mRNA, aldosterone and intracellular Ca2+ measurement (Fura-2), and molecular modeling were performed to characterize the KCNJ5-insT149 mutation. Results: The patient’s high blood pressure was long-term cured; his LVMI fell from 168 to 106 g/m2 after 2 years follow-up. Compared to wild type and mock-transfected HAC15 adrenocortical cells, those expressing the mutant KCNJ5 showed increased CYP11B2 expression (expression fold change: 2.9±0.3, p<0.05 vs mock transfected cells) and aldosterone secretion (260 pg/μg RNA, p<0.05 vs mock cells). The HEK293 cells expressing the mutated KCNJ5-insT149 channel exhibited a strong Na+ inward current, and a substantial rise in intracellular Ca2+. The L-type Ca2+ channel blocker verapamil [10 μM] inhibited by 50% the pathological Na+ inward current, while both the Na+/Ca2+ exchanger blocker KB-R7943 [10 μM] and the removal of extracellular Na+ abolished it. Conclusions: We identified a novel mutation of the Kir3.4 channelopathy located after the pore α-helix preceding the selectivity filter, which causes pathological Na+ permeability, membrane depolarization, raised cytosolic Ca2+, and constitutive hypersecretion of aldosterone resulting in ensuing pseudo resistant hypertension.
Felix Beuschlein - One of the best experts on this subject based on the ideXlab platform.
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primary aldosteronism KCNJ5 mutations and adrenocortical cell growth
Hypertension, 2019Co-Authors: Yuhong Yang, Felix Beuschlein, Celso E Gomezsanchez, Diana Jaquin, Elke Tatjana Aristizabal Prada, Lucie S Meyer, Thomas Knosel, Holger Schneider, Martin ReinckeAbstract:Aldosterone-producing adenomas with somatic mutations in the KCNJ5 G-protein-coupled inwardly rectifying potassium channel are a cause of primary aldosteronism. These mutations drive aldosterone excess, but their role in cell growth is undefined. Our objective was to determine the role of KCNJ5 mutations in adrenal cell proliferation and apoptosis. The Ki67 proliferative index was positively correlated with adenoma diameter in aldosterone-producing adenomas with a KCNJ5 mutation (r=0.435, P=0.007), a negative correlation was noted in adenomas with no mutation detected (r=-0.548, P=0.023). Human adrenocortical cell lines were established with stable expression of cumate-inducible wild-type or mutated KCNJ5. Increased cell proliferation was induced by low-level induction of KCNJ5-T158A expression compared with control cells (P=0.009), but increased induction ablated this difference. KCNJ5-G151R displayed no apparent proliferative effect, but KCNJ5-G151E and L168R mutations each resulted in decreased cell proliferation (difference P<0.0001 from control cells, both comparisons). Under conditions tested, T158A had no effect on apoptosis, but apoptosis increased with expression of G151R (P<0.0001), G151E (P=0.008), and L168R (P<0.0001). We generated a specific KCNJ5 monoclonal antibody which was used in immunohistochemistry to demonstrate strong KCNJ5 expression in adenomas without a KCNJ5 mutation and in the zona glomerulosa adjacent to adenomas irrespective of genotype as well as in aldosterone-producing cell clusters. Double immunofluorescence staining for KCNJ5 and CYP11B2 (aldosterone synthase) showed markedly decreased KCNJ5 immunostaining in CYP11B2-positive cells compared with CYP11B2-negative cells in aldosterone-producing adenomas with a KCNJ5 mutation. Together, these findings support the concept that cell growth effects of KCNJ5 mutations are determined by the expression level of the mutated channel.
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KCNJ5 mutations sex salt and selection
Hormone and Metabolic Research, 2015Co-Authors: Felix Beuschlein, Tracy Ann Williams, Jacques W M Lenders, Jacopo Burrello, Martin ReinckeAbstract:Somatic mutations have been identified in the KCNJ5 gene (encoding the potassium channel GIRK4) in aldosterone-producing adenomas (APA). Most of these mutations are located in or near the selectivity filter of the GIRK4 channel pore and several have been shown to lead to the constitutive overproduction of aldosterone. KCNJ5 mutations in APA are more frequent in women; however, this gender dimorphism is a reported phenomenon of Western but not East Asian populations. In this review we discuss some of the issues that could potentially underlie this observation.
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genetic spectrum and clinical correlates of somatic mutations in aldosterone producing adenoma
Hypertension, 2014Co-Authors: Fabio Luiz Fernandesrosa, Laurence Amar, Sheerazed Boulkroun, Felix Beuschlein, Silvia Monticone, Tracy Ann Williams, Anna Riester, Olivier Steichen, Tim M Strom, Tchao MeatchiAbstract:Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been described in aldosterone-producing adenomas (APAs). Our aim was to investigate the prevalence of somatic mutations in these genes in unselected patients with APA (n=474), collected through the European Network for the Study of Adrenal Tumors. Correlations with clinical and biochemical parameters were first analyzed in a subset of 199 patients from a single center and then replicated in 2 additional centers. Somatic heterozygous KCNJ5 mutations were present in 38% (180/474) of APAs, whereas ATP1A1 mutations were found in 5.3% (25/474) and ATP2B3 mutations in 1.7% (8/474) of APAs. Previously reported somatic CACNA1D mutations as well as 10 novel CACNA1D mutations were identified in 44 of 474 (9.3%) APAs. There was no difference in the cellular composition of APAs or in CYP11B2, CYP11B1, KCNJ5, CACNA1D, or ATP1A1 gene expression in APAs across genotypes. Patients with KCNJ5 mutations were more frequently female, diagnosed younger, and with higher minimal plasma potassium concentrations compared with CACNA1D mutation carriers or noncarriers. CACNA1D mutations were associated with smaller adenomas. These associations were largely dependent on the population structure of the different centers. In conclusion, recurrent somatic mutations were identified in 54% of APAs. Young women with APAs are more likely to be KCNJ5 mutation carriers; identification of specific characteristics or surrogate biomarkers of mutation status may lead to targeted treatment options.
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Pharmacology and pathophysiology of mutated KCNJ5 found in adrenal aldosterone-producing adenomas
Endocrinology, 2014Co-Authors: Philipp Tauber, Julia Stindl, Felix Beuschlein, David Penton, Evelyn Humberg, Ines Tegtmeier, Christina Sterner, Martin Reincke, Jacques Barhanin, Sascha BandulikAbstract:Somatic mutations of the potassium channel KCNJ5 are found in 40% of aldosterone producing adenomas (APAs). APA-related mutations of KCNJ5 lead to a pathological Na(+) permeability and a rise in cytosolic Ca(2+), the latter presumably by depolarizing the membrane and activating voltage-gated Ca(2+) channels. The aim of this study was to further investigate the effects of mutated KCNJ5 channels on intracellular Na(+) and Ca(2+) homeostasis in human adrenocortical NCI-H295R cells. Expression of mutant KCNJ5 led to a 2-fold increase in intracellular Na(+) and, in parallel, to a substantial rise in intracellular Ca(2+). The increase in Ca(2+) appeared to be caused by activation of voltage-gated Ca(2+) channels and by an impairment of Ca(2+) extrusion by Na(+)/Ca(2+) exchangers. The mutated KCNJ5 exhibited a pharmacological profile that differed from the one of wild-type channels. Mutated KCNJ5 was less Ba(2+) and tertiapin-Q sensitive but was inhibited by blockers of Na(+) and Ca(2+)-transporting proteins, such as verapamil and amiloride. The clinical use of these drugs might influence aldosterone levels in APA patients with KCNJ5 mutations. This might implicate diagnostic testing of APAs and could offer new therapeutic strategies.
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lack of influence of somatic mutations on steroid gradients during adrenal vein sampling in aldosterone producing adenoma patients
European Journal of Endocrinology, 2013Co-Authors: Andrea Oswald, Evelyn Fischer, Christoph Degenhart, Marcus Quinkler, Martin Bidlingmaier, Anna Pallauf, Katharina Lang, Thomas Mussack, K Hallfeldt, Felix BeuschleinAbstract:Objective: Adrenal vein sampling (AVS) is a technically demanding procedure required for the identification of suitable candidates for unilateral adrenalectomy in primary aldosteronism. Recently, somatic KCNJ5 K C -channel mutations in aldosterone-producing adenoma (APA) patients have been shown to influence steroid gradients during AVS. These and other recently identified genetic modifiers (ATP1A1 and ATP2B3) might affect the final diagnosis and treatment of the affected patients. Design: Fifty-nine patients with APAs who had undergone successful AVS (adrenal vein cortisol:peripheral cortisol ratio R2) and had undergone a mutation analysis of their tumor tissue were studied. The mutation status of the APAs was as follows: 19 KCNJ5 mutations, eight ATPase mutations (five ATP1A1 and three ATP2B3), and 32 patients with none of these mutations. Methods: The lateralization index (ratio of aldosterone:cortisol on the side of the adenoma to aldosterone to cortisol on the contralateral side) and the contralateral suppression index (ratio of aldosterone:cortisol on the contralateral side to aldosterone to cortisol in the periphery) were calculated for the KCNJ5-mutated, ATPase-mutated, and the KCNJ5/ATPase mutation-negative APA patients. Results: The lateralization indices of the ATPase mutation carriers had a median of 19.9 compared with a median of 16.0 in the KCNJ5 mutation carriers and that of 20.5 in the KCNJ5/ATPase mutation-negative patients. The contralateral suppression indices of the ATPase-mutated patients had a median of 0.1 compared with a median of 0.4 in the KCNJ5 mutation carriers and that of 0.2 in the KCNJ5/ATPase mutation-negative patients. The differences between the genetic groups were not statistically significant. Conclusions: We did not find evidence for a clinically important impact of mutation status on steroid gradients during AVS.
Tsugumichi Saito - One of the best experts on this subject based on the ideXlab platform.
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regulation of the KCNJ5 gene by sf 1 in the adrenal cortex complete genomic organization and promoter function
Molecular and Cellular Endocrinology, 2020Co-Authors: Ayaka Nishikido, Shunichi Matsumoto, Kazuhiko Horiguchi, Tomoko Miyamoto, Akikokatano Toki, Satoshi Yoshino, Takashi Okamura, Yasuyo Nakajima, Emi Ishida, Tsugumichi SaitoAbstract:Abstract Activating mutations in the KCNJ5 gene are responsible for the significant number of aldosterone-producing adenomas. To elucidate the molecular mechanisms underlying KCNJ5 expression, we characterized the entire human KCNJ5 gene. The gene spanned approximately 29.8 kb and contained three exons and two introns. The strongest expression of KCNJ5 mRNA was observed in the adrenal gland. The promoter region contained a putative binding site for SF-1 at −1782 bp. A construct containing −2444 bp of the promoter region exhibited the strongest promoter activity in adrenal H295R cells, and the introduction of a mutation in the SF-1 binding site almost completely abolished promoter activity. Furthermore, deletion mutation, EMSA, and knockdown analyses revealed that SF-1 bound to this element and was functional. Immunochemistry showed that KCNJ5 was predominantly expressed in the zona glomerulosa, while SF-1 was ubiquitously expressed in the adrenal cortex. These results demonstrated that SF-1 mediates the expression of human KCNJ5 in the adrenal cortex.
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regulation of the KCNJ5 gene by sf 1 in the adrenal cortex complete genomic organization and promoter function
Molecular and Cellular Endocrinology, 2020Co-Authors: Ayaka Nishikido, Shunichi Matsumoto, Kazuhiko Horiguchi, Tomoko Miyamoto, Akikokatano Toki, Satoshi Yoshino, Takashi Okamura, Yasuyo Nakajima, Emi Ishida, Tsugumichi SaitoAbstract:Abstract Activating mutations in the KCNJ5 gene are responsible for the significant number of aldosterone-producing adenomas. To elucidate the molecular mechanisms underlying KCNJ5 expression, we characterized the entire human KCNJ5 gene. The gene spanned approximately 29.8 kb and contained three exons and two introns. The strongest expression of KCNJ5 mRNA was observed in the adrenal gland. The promoter region contained a putative binding site for SF-1 at −1782 bp. A construct containing −2444 bp of the promoter region exhibited the strongest promoter activity in adrenal H295R cells, and the introduction of a mutation in the SF-1 binding site almost completely abolished promoter activity. Furthermore, deletion mutation, EMSA, and knockdown analyses revealed that SF-1 bound to this element and was functional. Immunochemistry showed that KCNJ5 was predominantly expressed in the zona glomerulosa, while SF-1 was ubiquitously expressed in the adrenal cortex. These results demonstrated that SF-1 mediates the expression of human KCNJ5 in the adrenal cortex.
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characteristics of japanese aldosterone producing adenomas with KCNJ5 mutations
Endocrine Journal, 2017Co-Authors: Takashi Okamura, Shunichi Matsumoto, Kazuhiko Horiguchi, Satoshi Yoshino, Yasuyo Nakajima, Akiko Katanotoki, Eijiro Yamada, Takuya Tomaru, Sumiyasu Ishii, Tsugumichi SaitoAbstract:Somatic mutations in KCNJ5 gene have been identified in patients with adrenal aldosterone-producing adenomas (APAs). We previously reported that Japanese patients with APAs had distinct characteristics from patients in Western countries; i.e. they had a high frequency of KCNJ5 mutations and exhibited a frequent association with cortisol co-secretion. Therefore, APAs among Japanese patients may have different features from those in Western countries. We added recent cases, examined 47 cases (43% male) of APAs, including clinicopathological features, KCNJ5 mutations, and the mRNA levels of several steroidogenic enzymes, and compared the results obtained to those reported in other countries. While the prevalence of KCNJ5 mutations is approximately 40% in Western countries, 37 APA cases (78.7%) showed mutations: 26 with p.G151R and 11 with p.L168R. Although a significant gender difference has been reported in the frequency of KCNJ5 mutations in Europe, we did not find any gender difference. However, the phenotypes of Japanese patients with mutations were similar to those of patients in Western countries; patients were younger and had higher plasma aldosterone levels, lower potassium levels, and higher diastolic blood pressure. Reflecting these phenotypes, APAs with mutations had higher CYP11B2 mRNA levels. However, in contrast to APAs in Western countries, Japanese APAs with mutations showed lower CYP11B1, CYP17A1, and CYP11A1 mRNA levels. These findings demonstrated that Japanese APA patients may have distinct features including a higher prevalence of KCNJ5 mutations, no gender difference in the frequency of these mutations, and characteristics similar to the zona glomerulosa.
Tracy Ann Williams - One of the best experts on this subject based on the ideXlab platform.
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KCNJ5 mutations sex salt and selection
Hormone and Metabolic Research, 2015Co-Authors: Felix Beuschlein, Tracy Ann Williams, Jacques W M Lenders, Jacopo Burrello, Martin ReinckeAbstract:Somatic mutations have been identified in the KCNJ5 gene (encoding the potassium channel GIRK4) in aldosterone-producing adenomas (APA). Most of these mutations are located in or near the selectivity filter of the GIRK4 channel pore and several have been shown to lead to the constitutive overproduction of aldosterone. KCNJ5 mutations in APA are more frequent in women; however, this gender dimorphism is a reported phenomenon of Western but not East Asian populations. In this review we discuss some of the issues that could potentially underlie this observation.
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a case of severe hyperaldosteronism caused by a de novo mutation affecting a critical salt bridge kir3 4 residue
The Journal of Clinical Endocrinology and Metabolism, 2015Co-Authors: Silvia Monticone, Julia Stindl, Sascha Bandulik, Constantine A Stratakis, Paolo Mulatero, Mihail Zilbermint, Ivan Ivanovich Dedov, Michael Allgaeuer, Chyichia Richard Lee, Tracy Ann WilliamsAbstract:Context: Familial hyperaldosteronism type III (FH-III) is a rare and clinically heterogeneous condition, that can display mild as well as severe phenotypes. Point mutations in the KCNJ5 gene, affecting the ion selectivity of the inward rectifier K+ channel 4 (Kir3.4), underlie the molecular basis of FH-III. Objective: The objective of the study was to investigate the effects of a de novo germline KCNJ5 mutation. Patients and Methods: We describe the case of a girl who came to medical attention at the age of 2 years because of polydipsia, polyuria, and failure to thrive. The patient, affected by hypertension and hypokalemia, was diagnosed with primary aldosteronism on the basis of extremely high aldosterone levels and suppressed plasma renin activity. Genomic DNA was isolated and KCNJ5 sequenced. Human adrenocortical cells were used as an in vitro model for the functional characterization of the mutant channel. Results: KCNJ5 sequencing in the index case and her parents revealed a de novo p.Glu145Gln germl...
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genetic spectrum and clinical correlates of somatic mutations in aldosterone producing adenoma
Hypertension, 2014Co-Authors: Fabio Luiz Fernandesrosa, Laurence Amar, Sheerazed Boulkroun, Felix Beuschlein, Silvia Monticone, Tracy Ann Williams, Anna Riester, Olivier Steichen, Tim M Strom, Tchao MeatchiAbstract:Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been described in aldosterone-producing adenomas (APAs). Our aim was to investigate the prevalence of somatic mutations in these genes in unselected patients with APA (n=474), collected through the European Network for the Study of Adrenal Tumors. Correlations with clinical and biochemical parameters were first analyzed in a subset of 199 patients from a single center and then replicated in 2 additional centers. Somatic heterozygous KCNJ5 mutations were present in 38% (180/474) of APAs, whereas ATP1A1 mutations were found in 5.3% (25/474) and ATP2B3 mutations in 1.7% (8/474) of APAs. Previously reported somatic CACNA1D mutations as well as 10 novel CACNA1D mutations were identified in 44 of 474 (9.3%) APAs. There was no difference in the cellular composition of APAs or in CYP11B2, CYP11B1, KCNJ5, CACNA1D, or ATP1A1 gene expression in APAs across genotypes. Patients with KCNJ5 mutations were more frequently female, diagnosed younger, and with higher minimal plasma potassium concentrations compared with CACNA1D mutation carriers or noncarriers. CACNA1D mutations were associated with smaller adenomas. These associations were largely dependent on the population structure of the different centers. In conclusion, recurrent somatic mutations were identified in 54% of APAs. Young women with APAs are more likely to be KCNJ5 mutation carriers; identification of specific characteristics or surrogate biomarkers of mutation status may lead to targeted treatment options.
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a novel y152c KCNJ5 mutation responsible for familial hyperaldosteronism type iii
The Journal of Clinical Endocrinology and Metabolism, 2013Co-Authors: Silvia Monticone, David Penton, Christina Sterner, Tracy Ann Williams, Namita G Hattangady, Carlos M Isales, Michael A Edwards, Richard WarthAbstract:Context: Primary aldosteronism is a heterogeneous group of disorders comprising both sporadic and familial forms. Mutations in the KCNJ5 gene, which encodes the inward rectifier K+ channel 4 (G protein-activated inward rectifier K+ channel 4, Kir3.4), cause familial hyperaldosteronism type III (FH-III) and are involved in the pathogenesis of sporadic aldosterone-producing adenomas. Objective: The objective of the study was to characterize the effects of a newly described KCNJ5 mutation in vitro. Patients and Methods: The index case is a 62-year-old woman affected by primary aldosteronism, who underwent left adrenalectomy after workup for adrenal adenoma. Exon 1 of KCNJ5 was PCR amplified from adrenal tissue and peripheral blood and sequenced. Electrophysiological and gene expression studies were performed to establish the functional effects of the new mutation on the membrane potential and adrenal cell CYP11B2 expression. Results: KCNJ5 sequencing in the index case revealed a new p.Y152C germline mutation...
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role of KCNJ5 in familial and sporadic primary aldosteronism
Nature Reviews Endocrinology, 2013Co-Authors: Paolo Mulatero, Franco Veglio, Silvia Monticone, William E Rainey, Tracy Ann WilliamsAbstract:Primary aldosteronism is characterised by the dysregulation of aldosterone production and comprises both sporadic forms, caused by an aldosterone-producing adenoma or bilateral adrenal hyperplasia, and familial forms (familial hyperaldosteronism types I, II and III). The two principal physiological regulators of aldosterone synthesis are angiotensin II and serum K(+), which reverse the high resting K(+) conductance and hyperpolarized membrane potential of adrenal glomerulosa cells. The resulting membrane depolarization causes the opening of voltage-gated Ca(2+) channels and an increase in intracellular Ca(2+) that stimulates aldosterone biosynthesis. Point mutations in the KCNJ5 gene, which encodes the G-protein-activated inward rectifier K(+) channel 4 (GIRK4), have been implicated in the pathogenesis of both sporadic and familial forms of primary aldosteronism. These mutations interfere with the selectivity filter of GIRK4 causing Na(+) entry, cell depolarization and Ca(2+) channel opening, resulting in constitutive aldosterone production. Seven families with familial hyperaldosteronism caused by KCNJ5 germline mutations have so far been described, and multicentre studies have reported KCNJ5 mutations in approximately 40% of sporadic aldosterone-producing adenomas. Herein, we review the role of GIRK4 in adrenal pathophysiology and provide an overview of the clinical and biochemical phenotypes resulting from KCNJ5 mutations in patients with sporadic and familial primary aldosteronism.