scholarly journals Role of Ca2+/Calmodulin-Dependent Protein Kinase Kinase in Adrenal Aldosterone Production

Endocrinology ◽  
2015 ◽  
Vol 156 (5) ◽  
pp. 1750-1756 ◽  
Author(s):  
Kazutaka Nanba ◽  
Andrew Chen ◽  
Koshiro Nishimoto ◽  
William E. Rainey

There is considerable evidence supporting the role of calcium signaling in adrenal regulation of both aldosterone synthase (CYP11B2) and aldosterone production. However, there have been no studies that investigated the role played by the Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) in adrenal cells. In this study we investigated the role of CaMKK in adrenal cell aldosterone production. To determine the role of CaMKK, we used a selective CaMKK inhibitor (STO-609) in the HAC15 human adrenal cell line. Cells were treated with angiotensin II (Ang II) or K+ and evaluated for the expression of steroidogenic acute regulatory protein and CYP11B2 (mRNA/protein) as well as aldosterone production. We also transduced HAC15 cells with lentiviral short hairpin RNAs of CaMKK1 and CaMKK2 to determine which CaMKK plays a more important role in adrenal cell regulation of the calcium signaling cascade. The CaMKK inhibitor, STO-609, decreased aldosterone production in cells treated with Ang II or K+ in a dose-dependent manner. STO-609 (20μM) also inhibited steroidogenic acute regulatory protein and CYP11B2 mRNA/protein induction. CaMKK2 knockdown cells showed significant reduction of CYP11B2 mRNA induction and aldosterone production in cells treated with Ang II, although there was no obvious effect in CaMKK1 knockdown cells. In immunohistochemical analysis, CaMKK2 protein was highly expressed in human adrenal zona glomerulosa with lower expression in the zona fasciculata. In conclusion, the present study suggests that CaMKK2 plays a pivotal role in the calcium signaling cascade regulating adrenal aldosterone production.

2008 ◽  
Vol 93 (11) ◽  
pp. 4542-4546 ◽  
Author(s):  
Jeniel Parmar ◽  
Rebecca E. Key ◽  
William E. Rainey

Context: The molecular mechanisms regulating adrenal steroidogenesis continue to be defined. The only current human adrenocortical cell line is the NCI-H295 and its substrains. One of the strains, H295R, has retained the ability to respond to angiotensin II (Ang II); however, it lacks ACTH responsiveness. An ACTH-responsive human adrenocortical model would add significantly to studies directed at defining the molecular control of corticosteroid biosynthesis. Objective: The objective of the study was to develop a human adrenal cell line that retained both Ang II- and ACTH-regulated corticosteroid production. Design: Human adrenocortical carcinoma (HAC) cells were isolated from an adrenal tumor removed from a girl presenting with virilization and hypertension. Clonal populations of cells were established and characterized. HAC cells were treated with ACTH, Ang II, and forskolin, followed by examination of steroidogenic enzyme mRNA expression using quantitative real-time PCR and steroid production. Results: HAC clone 15 (HAC15) cells responded to treatment with ACTH, Ang II, and forskolin, with increased cortisol and aldosterone production. ACTH, Ang II, and forskolin also increased expression of mRNA, encoding all enzymes needed for cortisol and aldosterone biosynthesis, namely steroidogenic acute regulatory protein, cholesterol side-chain cleavage, cytochrome P450 17α-hydroxylase-17, 20-lyase, 3β-hydroxysteroid dehydrogenase type II, 21-hydroxylase, 11β-hydroxylase, and 11β-aldosterone synthase. In addition, the cells expressed mRNA for ACTH receptor (MC2R) and Ang II receptor. MC2R protein was also expressed in HAC15 cells. Conclusion: The current study describes the development and characterization of an ACTH- and Ang II-responsive human adrenal cell line. The HAC15 cell line should provide an important model system for defining the molecular mechanisms regulating aldosterone and cortisol production.


Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 3284-3294 ◽  
Author(s):  
Pablo G. Mele ◽  
Alejandra Duarte ◽  
Cristina Paz ◽  
Alessandro Capponi ◽  
Ernesto J. Podestá

Although the role of arachidonic acid (AA) in angiotensin II (ANG II)- and potassium-stimulated steroid production in zona glomerulosa cells is well documented, the mechanism responsible for AA release is not fully described. In this study we evaluated the mechanism involved in the release of intramitochondrial AA and its role in the regulation of aldosterone synthesis by ANG II in glomerulosa cells. We show that ANG II and potassium induce the expression of acyl-coenzyme A (CoA) thioesterase 2 and acyl-CoA synthetase 4, two enzymes involved in intramitochondrial AA generation/export system well characterized in other steroidogenic systems. We demonstrate that mitochondrial ATP is required for AA generation/export system, steroid production, and steroidogenic acute regulatory protein induction. We also demonstrate the role of protein tyrosine phosphatases regulating acyl-CoA synthetase 4 and steroidogenic acute regulatory protein induction, and hence ANG II-stimulated aldosterone synthesis.


1996 ◽  
Vol 58 (4) ◽  
pp. 417-424 ◽  
Author(s):  
Vincenzo Pezzi ◽  
Barbara J. Clark ◽  
Sebastiano Ando ◽  
Douglas M. Stocco ◽  
William E. Rainey

2000 ◽  
Vol 24 (2) ◽  
pp. 233-239 ◽  
Author(s):  
PM Jones ◽  
SB Sayed ◽  
SJ Persaud ◽  
CJ Burns ◽  
S Gyles ◽  
...  

In addition to the well-documented role of protein kinases in the regulation of steroid production, phosphoprotein phosphatase (PP) activity is required for steroidogenesis. In the present study, we have used the mouse Y1 adrenocortical cell line to identify the site of action of PPs on steroid production by measuring the effects of PP inhibition on the expression of the steroidogenic acute regulatory (StAR) protein and on steroid production. Forskolin-induced activation of cyclic AMP-dependent protein kinase (PKA) enhanced steroidogenesis and this was accompanied by an increased expression of StAR protein. Both steroidogenesis and StAR protein expression were inhibited by two structurally dissimilar inhibitors of PP1 and PP2A activities, okadaic acid and calyculin A. These results suggest that inhibition of PP1 and PP2A inhibits steroid production by preventing the expression of the StAR protein, implicating PP1/2A dephosphorylation reactions as important regulators of stimulus-dependent StAR protein expression, and thus of steroidogenesis.


Endocrinology ◽  
2004 ◽  
Vol 145 (2) ◽  
pp. 639-649 ◽  
Author(s):  
Jiro Suzuki ◽  
Fumio Otsuka ◽  
Kenichi Inagaki ◽  
Masaya Takeda ◽  
Toshio Ogura ◽  
...  

Abstract We have uncovered a functional bone morphogenetic protein (BMP) and activin system complete with ligands (BMP-6 and activin βA/βB), receptors (activin receptor-like kinase receptors 2, 3, and 4; activin type-II receptor; and BMP type-II receptor), and the binding protein follistatin in the human adrenocortical cell line H295R. Administration of activin and BMP-6 to cultures of H295R cells caused concentration-responsive increases in aldosterone production. The mRNA levels of steroidogenic acute regulatory protein or P450 steroid side-chain cleavage enzyme, the rate-limiting steps of adrenocortical steroidogenesis, were enhanced by activin and BMP-6. Activin and BMP-6 also activated the transcription of steroidogenic acute regulatory protein as well as the late-step steriodogenic enzyme CYP11B2. Activin enhanced ACTH-, forskolin-, or dibutyryl-cAMP- but not angiotensin II (Ang II)-induced aldosterone production, whereas BMP-6 specifically augmented Ang II-induced aldosterone production. Activin and ACTH but not BMP-6 increased cAMP production. Follistatin, which inhibits activin actions by binding, suppressed basal and ACTH-induced aldosterone secretion but failed to affect the Ang II-induced aldosterone level. Furthermore, MAPK signaling appeared to be involved in aldosterone production induced by Ang II and BMP-6 because an inhibitor of MAPK activation, U0126, reduced the level of aldosterone synthesis stimulated by Ang II and BMP-6 but not activin. In addition, Ang II reduced the expression levels of BMP-6 but increased that of activin βB, whereas ACTH had no effect on these levels. Collectively, the present data suggest that activin acts to regulate adrenal aldosterone synthesis predominantly by modulating the ACTH-cAMP-protein kinase A signaling cascade, whereas BMP-6 works primarily by modulating the Ang II-MAPK cascade in human adrenal cortex in an autocrine/paracrine fashion.


2016 ◽  
Vol 57 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Namita G Hattangady ◽  
Shigehiro Karashima ◽  
Lucy Yuan ◽  
Daniela Ponce-Balbuena ◽  
José Jalife ◽  
...  

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 (KCNJ5T158A) on acute and chronic regulation of aldosterone production using an adrenal cell line with a doxycycline-inducible KCNJ5T158A gene (HAC15-TRE-KCNJ5T158A). Doxycycline incubation caused a time-dependent increase in KCNJ5T158A and CYP11B2 mRNA and protein levels. Electrophysiological analyses confirm the loss of inward rectification and increased Na+ permeability in KCNJ5T158A-expressing cells. KCNJ5T158A expression also led to the activation of CYP11B2 transcriptional regulators, NURR1 and ATF2. Acutely, KCNJ5T158A stimulated the expression of total and phosphorylated steroidogenic acute regulatory protein (StAR). KCNJ5T158A 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 KCNJ5T158A were inhibited by the L-type Ca2+ channel blocker, verapamil. Overall, KCNJ5T158Aincreases CYP11B2 expression and production of aldosterone, corticosterone and hybrid steroids by upregulating both acute and chronic regulatory events in aldosterone production, and verapamil blocks KCNJ5T158A-mediated pathways leading to aldosterone production.


1999 ◽  
Vol 82 (3) ◽  
pp. 1560-1568 ◽  
Author(s):  
Mingyan Zhu ◽  
Craig H. Gelband ◽  
Philip Posner ◽  
Colin Sumners

Angiotensin II (Ang II) acts at specific receptors located on neurons in the hypothalamus and brain stem to elicit alterations in blood pressure, fluid intake, and hormone secretion. These actions of Ang II are mediated via Ang II type 1 (AT1) receptors and involve modulation of membrane ionic currents and neuronal activity. In previous studies we utilized neurons cultured from the hypothalamus and brain stem of newborn rats to investigate the AT1receptor–mediated effects of Ang II on neuronal K+currents. Our data indicate that Ang II decreases neuronal delayed rectifier (Kv) current, and that this effect is partially due to activation of protein kinase C (PKC), specifically PKCα. However, the data also indicated that another Ca2+-dependent mechanism was also involved in addition to PKC. Because Ca2+/calmodulin-dependent protein kinase II (CaM KII) is a known modulator of K+ currents in neurons, we investigated the role of this enzyme in the AT1 receptor–mediated reduction of neuronal Kv current by Ang II. The reduction of neuronal Kv current by Ang II was attenuated by selective inhibition of either calmodulin or CaM KII and was mimicked by intracellular application of activated (autothiophosphorylated) CaM KIIα. Concurrent inhibition of CaM KII and PKC completely abolished the reduction of neuronal Kv by Ang II. Consistent with these findings is the demonstration that Ang II increases CaM KII activity in neuronal cultures, as evidenced by increased levels of autophosphorylated CaM KIIα subunit. Last, single-cell reverse transcriptase (RT)-PCR analysis revealed the presence of AT1 receptor-, CaM KIIα-, and PKCα subunit mRNAs in neurons that responded to Ang II with a decrease in Kv current. The present data indicate that the AT1receptor–mediated reduction of neuronal Kv current by Ang II involves a Ca2+/calmodulin/CaM KII pathway, in addition to the previously documented involvement of PKC.


Sign in / Sign up

Export Citation Format

Share Document