Hydrodynamic properties of the angiotensin II receptor from bovine adrenal zona glomerulosa.
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ABSTRACT:
SUBMITTER: Rondeau JJ
PROVIDER: S-EPMC1131452 | biostudies-other | 1990 Jun
REPOSITORIES: biostudies-other
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Project description:Hyperaldosteronism is associated with hypertension, cardiac hypertrophy, and congestive heart failure. Steroidogenic factors facilitate aldosterone secretion by increasing adrenal blood flow. Angiotensin (Ang) II decreases adrenal vascular tone through release of zona glomerulosa (ZG) cell-derived vasodilatory eicosanoids. However, ZG cell-mediated relaxation of bovine adrenal cortical arteries to Ang II is not altered by angiotensin type 1 or 2 receptor antagonists. Because traditional Ang II receptors do not mediate these vasorelaxations to Ang II, we investigated the role of Ang II metabolites. Ang III was identified by liquid chromatography-mass spectrometry as the primary ZG cell metabolite of Ang II. Ang III stimulated ZG cell-mediated relaxation of adrenal arteries with greater potency than did Ang II. Furthermore, ZG cell-mediated relaxations of adrenal arteries by Ang II were attenuated by aminopeptidase inhibition, and Ang III-stimulated relaxations persisted. Ang IV had little effect compared with Ang II. Moreover, ZG cell-mediated relaxations of adrenal arteries by Ang II were attenuated by an Ang III antagonist but not by an Ang (1-7) antagonist. In contrast, Ang II and Ang III were equipotent in stimulating aldosterone secretion from ZG cells and were unaffected by aminopeptidase inhibition. Additionally, aspartyl and leucyl aminopeptidases, which convert Ang II to Ang III, are the primary peptidase expressed in ZG cells. This was confirmed by enzyme activity. These data indicate that intra-adrenal metabolism of Ang II to Ang III is required for ZG cell-mediated relaxations of adrenal arteries but not aldosterone secretion. These studies have defined an important role of Ang III in the adrenal gland.
| S-EPMC5761603 | biostudies-literature
Project description:Elevated concentrations of aldosterone are associated with several cardiovascular diseases. Angiotensin II (Ang II) increases aldosterone secretion and adrenal blood flow. This concurrent increase in steroidogenesis and adrenal blood flow is not understood. We investigated the role of zona glomerulosa (ZG) cells in the regulation of vascular tone of bovine adrenal cortical arteries by Ang II. ZG cells enhanced endothelium-dependent relaxations to Ang II. The ZG cell-dependent relaxations to Ang II were unchanged by removing the endothelium-dependent response to Ang II. These ZG cell-mediated relaxations were ablated by cytochrome P450 inhibition, epoxyeicosatrienoic acid (EET) antagonism, and potassium channel blockade. Analysis of ZG cell EET production by liquid chromatography/mass spectrometry demonstrated an increase in EETs and dihydroxyeicosatrienoic acids with Ang II stimulation. These EETs and dihydroxyeicosatrienoic acids produced similar concentration-dependent relaxations of adrenal arteries, which were attenuated by EET antagonism. Whole-cell potassium currents of adrenal artery smooth muscle cells were increased by Ang II stimulation in the presence of ZG cells but decreased in the absence of ZG cells. This increase in potassium current was abolished by iberiotoxin. Similarly, 14,15-EET induced concentration-dependent increases in potassium current, which was abolished by iberiotoxin. ZG cell aldosterone release was not directly altered by EETs. These data suggest that Ang II stimulates ZG cells to release EETs and dihydroxyeicosatrienoic acids, resulting in potassium channel activation and relaxation of adrenal arteries. This provides a mechanism by which Ang II concurrently increases adrenal blood flow and steroidogenesis.
| S-EPMC3034648 | biostudies-literature
Project description:In mammals, aldosterone is produced in the zona glomerulosa (zG), the outermost layer of the adrenal cortex, whereas glucocorticoids are produced in adjacent zona fasciculata (zF). However, the cellular mechanisms controlling the zonal development and the differential hormone production (i.e. functional zonation) are poorly understood. To explore the mechanisms, we defined zone-specific transcripts in this study. Eleven-week-old male rats were used and adrenal tissues were collected from zG and zF using laser-capture microdissection. RNA was isolated, biotin labeled, amplified, and hybridized to Illumina microarray chips. The microarray data were compared by fold change calculations. In zG, 235 transcripts showed more than a 2-fold up-regulation compared to zF with statistical significance. Similarly, 231 transcripts showed up-regulation in zF. The microarray findings were validated using quantitative RT-PCR and immunohistochemical staining on selected transcripts, including Cyp11b2 (zG/zF: 214.2x), Rgs4 (68.4x), Smoc2 (49.3x), and Mia1 (43.1x) in zG as well as Ddah1 (zF/zG 16.2x), Cidea (15.5x), Frzb (9.5x), and Hsd11b2 (8.3x) in zF. The lists of transcripts obtained in the current study will be an invaluable tool for the elucidation of cellular mechanisms leading to zG and zF functional zonation.
| S-EPMC3320243 | biostudies-literature
Project description:Aldosterone, which plays a central role in the regulation of blood pressure, is produced by zona glomerulosa (ZG) cells of the adrenal gland. When dysregulated, aldosterone is pathogenic and contributes to the development and progression of cardiovascular and renal disease. Although sustained production of aldosterone requires persistent Ca2+ entry through low-voltage activated Ca2+ channels, isolated ZG cells are considered nonexcitable, with recorded membrane voltages that are too hyperpolarized to permit Ca2+ entry. Here, we show that mouse ZG cells within adrenal slices spontaneously generate membrane potential oscillations of low periodicity. This innate electrical excitability of ZG cells provides a platform for the production of a recurrent Ca2+ signal that can be controlled by Ang II and extracellular potassium, the 2 major regulators of aldosterone production. We conclude that native ZG cells are electrical oscillators, and that this behavior provides what we believe to be a new molecular explanation for the control of Ca2+ entry in these steroidogenic cells.
| S-EPMC3966877 | biostudies-literature
Project description:In order to analyze the transcriptome characteristics of aldosterone producing cell clusters (APCC) we compared transcript abundances of APCC, zona glomerulosa (ZG), zona fasciculata (ZF), and zona reticularis (ZR), from adrenal glands obtained from 4 kidney transplantation donors. The frozen adrenal glands in O.C.T. compound were cut into 7um sections, and every 10-th section immunostained for aldosterone synthase (CYP11B2). The remaining sections were stained with cresyl violet and used for laser-capture microdissection of tissue to use in the array assays. APCC and ZG samples were captured from CYP11B2 positive regions based on the CYP11B2-stained sections. ZF and ZR were captured from lipid-rich cells in the middle layer and compact cells outside of the medulla, respectively. RNA was isolated using PicoPure RNA isolation kits (Molecular Devices, Sunnyvale, CA). 1-10 ng total RNA was reverse-transcribed and amplified with the Ovation Pico WTA System V2 (NuGEN Technologies, San Carlos, CA). cDNA was purified using QIAquick PCR Purification Kit (Qiagen, Hilden, Germany) and biotin-labeled using Encore Biotin Module (NuGEN Technologies), followed by hybridization to GeneChip Human Genome U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA). Expression values were calculated using the robust multi-array average method (RMA). This resulted in base-2 log-transformed data for each of the 4 tissues from each of the 4 people. In addition to the raw and processed data we also supply a supplementary Excel file holding the data and some statistical analysis, which has features to make simple graphs, and holds probe-set annotation that we used at that time (users may wish to obtain new annotation though). We fit two-way ANOVA models with terms for 4 tissues and 4 people, and compared each probe-set between every pair of tissues using F-tests for pairwise contrasts. We modeled people effects since they were not negligible. The supplement shows how to calculate the tests.
2015-06-26 | GSE68889 | GEO
Project description:Aldosterone is a steroid hormone important in the regulation of blood pressure. Aberrant production of aldosterone results in the development and progression of diseases including hypertension and congestive heart failure; therefore, a complete understanding of aldosterone production is important for developing more effective treatments. Angiotensin II (AngII) regulates steroidogenesis, in part through its ability to increase intracellular calcium levels. Calcium can activate calpains, proteases classified as typical or atypical based on the presence or absence of penta-EF-hands, which are involved in various cellular responses. We hypothesized that calpain, in particular calpain-10, is activated by AngII in adrenal glomerulosa cells and underlies aldosterone production. Our studies showed that pan-calpain inhibitors reduced AngII-induced aldosterone production in 2 adrenal glomerulosa cell models, primary bovine zona glomerulosa and human adrenocortical carcinoma (HAC15) cells, as well as CYP11B2 expression in the HAC15 cells. Although AngII induced calpain activation in these cells, typical calpain inhibitors had no effect on AngII-elicited aldosterone production, suggesting a lack of involvement of classical calpains in this process. However, an inhibitor of the atypical calpain, calpain-10, decreased AngII-induced aldosterone production. Consistent with this result, small interfering RNA (siRNA)-mediated knockdown of calpain-10 inhibited aldosterone production and CYP11B2 expression, whereas adenovirus-mediated overexpression of calpain-10 resulted in increased AngII-induced aldosterone production. Our results indicate that AngII-induced activation of calpain-10 in glomerulosa cells underlies aldosterone production and identify calpain-10 or its downstream pathways as potential targets for the development of drug therapies for the treatment of hypertension.
| S-EPMC4430612 | biostudies-literature
Project description:In order to analyze the transcriptome characteristics of aldosterone producing cell clusters (APCC) we compared transcript abundances of APCC, zona glomerulosa (ZG), zona fasciculata (ZF), and zona reticularis (ZR), from adrenal glands obtained from 4 kidney transplantation donors. The frozen adrenal glands in O.C.T. compound were cut into 7um sections, and every 10-th section immunostained for aldosterone synthase (CYP11B2). The remaining sections were stained with cresyl violet and used for laser-capture microdissection of tissue to use in the array assays. APCC and ZG samples were captured from CYP11B2 positive regions based on the CYP11B2-stained sections. ZF and ZR were captured from lipid-rich cells in the middle layer and compact cells outside of the medulla, respectively. RNA was isolated using PicoPure RNA isolation kits (Molecular Devices, Sunnyvale, CA). 1-10 ng total RNA was reverse-transcribed and amplified with the Ovation Pico WTA System V2 (NuGEN Technologies, San Carlos, CA). cDNA was purified using QIAquick PCR Purification Kit (Qiagen, Hilden, Germany) and biotin-labeled using Encore Biotin Module (NuGEN Technologies), followed by hybridization to GeneChip Human Genome U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA). Expression values were calculated using the robust multi-array average method (RMA). This resulted in base-2 log-transformed data for each of the 4 tissues from each of the 4 people. In addition to the raw and processed data we also supply a supplementary Excel file holding the data and some statistical analysis, which has features to make simple graphs, and holds probe-set annotation that we used at that time (users may wish to obtain new annotation though). We fit two-way ANOVA models with terms for 4 tissues and 4 people, and compared each probe-set between every pair of tissues using F-tests for pairwise contrasts. We modeled people effects since they were not negligible. The supplement shows how to calculate the tests. Aldosterone producing cell clusters (APCC), zona glomerulosa (ZG), zona fasciculata (ZF), and zona reticularis (ZR), from adrenal glands obtained from 4 kidney transplantation donors, were individually assayed on 16 Affymetrix GeneChip Human Genome U133 Plus 2.0 Arrays. Expression values were estimated with the Robust Multi-Arry average (RMA) algorithm, which resulted in log-2 transformed values for each of 54675 probe sets.
2015-06-26 | E-GEOD-68889 | biostudies-arrayexpress
Project description:We have demonstrated previously that in bovine adrenal glomerulosa cells, phospholipase D (PLD) activity can indirectly result in the generation of sn-1,2-diacylglycerol (DAG) through its production of phosphatidic acid (PA) and the subsequent action of PA phosphohydrolase. Furthermore, the PLD-generated DAG can trigger aldosterone secretion. Therefore, we characterized PLD activation by two agonists, angiotensin II (Ang II) and carbachol, to determine if the activity of the enzyme might underlie sustained aldosterone secretion. We determined that Ang II-induced PLD activation occurred via the angiotensin-1 receptor (AT1), and that a specific AT1 antagonist, losartan, inhibited this activation, whereas the same concentration of the AT2-specific antagonist, PD 123319, had no effect. Ang II activated PLD with a dose dependence similar to that observed for aldosterone secretion, with slight increases in activity induced by 0.1 nM Ang II and maximal activation at 10 nM. We also found that Ang II induced a sustained activation of PLD, but that the effect of carbachol, a stable analogue of acetylcholine, was transient; PLD activity increased within 5 min of exposure to carbachol but then ceased by 15 min. Higher carbachol concentrations were also unable to sustain PLD activation. These results suggest that the Ang II-elicited activation of PLD is associated with a sustained increase in aldosterone secretion from glomerulosa cells and further provide the first evidence, to our knowledge, of differences in the kinetics of PLD activation in response to two physiologically relevant agonists. Finally, we speculate that this disparity correlates with different functional responses induced by the two agents.
| S-EPMC1219159 | biostudies-other
Project description:Learn about the transcriptome profiling of zona glomerulosa (ZG), zona fasciculata (ZF) and aldosterone-producing adenomas (APA) in human adrenals
2015-09-15 | GSE64957 | GEO
Project description:Angiotensin II (AngII) plays a crucial role in the control of aldosterone biosynthesis in adrenal glomerulosa cells through the stimulation of two distinct Ca2+ entry pathways: (1) opening of voltage-operated calcium channels, and (2) activation of a capacitative Ca2+ entry that is dependent on calcium release from intracellular pools. Adrenocorticotrophic hormone (ACTH), on the other hand, a major hormonal regulator of steroidogenesis, induces an increase in intracellular cAMP through the activation of a G-protein-coupled adenylyl cyclase. Recent studies have demonstrated that the rise in cAMP induced by ACTH can be potentiated by AngII in bovine glomerulosa cells. The aim of the present study was to investigate the mechanism of AngII action on ACTH-induced cAMP production. In primary cultures of bovine glomerulosa cells, we found that AngII (100 nM), which had no effect by itself on cAMP production, significantly potentiated maximal ACTH-induced cAMP formation in the presence of extracellular calcium (1.2 mM). In contrast, in the absence of extracellular calcium, AngII did not affect ACTH-induced cAMP production. These results suggest that calcium entry into the cell plays an important role in the activation of the cyclase by AngII. The inhibition of voltage-operated calcium channels by nicardipine, a dihydropyridine calcium antagonist blocking both low-threshold (T-type) and high-threshold (L-type) Ca2+ channels, did not significantly affect the potentiating effect of AngII. Moreover, the cAMP response to ACTH was insensitive to activation of these Ca2+ channels induced by potassium ions and, even when cytosolic free-calcium concentration ([Ca2+]c) was kept elevated with the Ca2+ ionophore, ionomycin, no stimulation of adenylyl cyclase was observed at concentrations of [Ca2+]c up to 640 nM. In contrast, thapsigargin, an activator of capacitative Ca2+ influx, mimicked the potentiating effect of AngII on ACTH-induced cAMP formation. In agreement with the characteristics of cAMP modulation by Ca2+ in these cells, the presence of type III adenylyl cyclase was observed by immunodetection in bovine glomerulosa cell membranes. In conclusion, these data suggest a tight coupling between the capacitative Ca2+ influx induced upon stimulation by either AngII or thapsigargin and a calcium-sensitive isoform of adenylyl cyclase, probably type III, in bovine glomerulosa cells.
| S-EPMC1219102 | biostudies-other