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.

Project description:Primary aldosteronism (PA) is a common form of endocrine hypertension suspected in the presence of arterial hypertension (HT), hypokalemia and low plasma renin levels. While for a long time the genetic causes of PA have remained mysterious, recent findings have revealed an important role for an altered function of potassium channels in the pathogenesis of this disease. The basis for the unique sensitivity of adrenal zona glomerulosa (ZG) cells for plasma potassium concentration is a very high background potassium conductance, which is dependent on expression at high levels of two 2-pore domain (K2P) potassium channels, Task1 (KCNK3) and Task3 (KCNK9. Recent studies have shown that mice lacking Kcnk3 (Task1) or both Kcnk3 and Kcnk9 have PA. In Kcnk3 null mice, hyperaldosteronism is present in young animals of either sex, but is corrected in males after puberty. Strikingly, in these animals hyperaldosteronism associates with abnormal adrenal cortex functional zonation, since Cyp11b2, the rate-limiting enzyme for aldosterone production, is expressed in the inner region of the adrenal cortex and not in the glomerulosa. Additionally, this phenotype is under the control of sex hormones, as shown by the fact that castration of male Kcnk3 -/- animals prevents normal Cyp11b2 distribution, while testosterone injection in female Kcnk3 null mice restores expression of Cyp11b2 in ZG cells. We took advantage of the unique characteristics of the Kcnk3 null mouse model to search for genes that can modify their phenotype of PA and adrenocortical functional zonation. Using gene expression profiling in the adrenal glands of Kcnk3 null mice and exploiting the possibility of modulation of their phenotype by sexual hormones, we identified a cluster of genes closely associated with hyperaldosteronism in a sex- and hormone-dependent dynamic fashion. Among these genes, we focused our attention on Dkk3 (dickkopf3), encoding a peculiar member of the dickkopf family of Wnt signalling modulators because of its close association with aldosterone-producing cells in humans (11). Inactivation of Dkk3 in the Kcnk3 null background causes extension of the hyperaldosteronemic phenotype and increased expression of Cyp11b2 in the adrenal gland to the male sex, without affecting functional zonation. These data indicate that Dkk3 is a component of the genetic circuitry regulating expression of Cyp11b2 and suggest that it may be implicated in the pathogenesis of low-renin hyperaldosteronism in humans. One color -experiment with 2 strains of mice: C57BL/6 WT or Kcnk3 null (KO): male and female in basal conditions or following hormonal treatment (castration for males and testosterone injection for females), corresponding to 8 groups of animals. Total of 24 samples (n=3).

Project description:Primary aldosteronism (PA) is a common form of endocrine hypertension suspected in the presence of arterial hypertension (HT), hypokalemia and low plasma renin levels. While for a long time the genetic causes of PA have remained mysterious, recent findings have revealed an important role for an altered function of potassium channels in the pathogenesis of this disease. The basis for the unique sensitivity of adrenal zona glomerulosa (ZG) cells for plasma potassium concentration is a very high background potassium conductance, which is dependent on expression at high levels of two 2-pore domain (K2P) potassium channels, Task1 (KCNK3) and Task3 (KCNK9. Recent studies have shown that mice lacking Kcnk3 (Task1) or both Kcnk3 and Kcnk9 have PA. In Kcnk3 null mice, hyperaldosteronism is present in young animals of either sex, but is corrected in males after puberty. Strikingly, in these animals hyperaldosteronism associates with abnormal adrenal cortex functional zonation, since Cyp11b2, the rate-limiting enzyme for aldosterone production, is expressed in the inner region of the adrenal cortex and not in the glomerulosa. Additionally, this phenotype is under the control of sex hormones, as shown by the fact that castration of male Kcnk3 -/- animals prevents normal Cyp11b2 distribution, while testosterone injection in female Kcnk3 null mice restores expression of Cyp11b2 in ZG cells. We took advantage of the unique characteristics of the Kcnk3 null mouse model to search for genes that can modify their phenotype of PA and adrenocortical functional zonation. Using gene expression profiling in the adrenal glands of Kcnk3 null mice and exploiting the possibility of modulation of their phenotype by sexual hormones, we identified a cluster of genes closely associated with hyperaldosteronism in a sex- and hormone-dependent dynamic fashion. Among these genes, we focused our attention on Dkk3 (dickkopf3), encoding a peculiar member of the dickkopf family of Wnt signalling modulators because of its close association with aldosterone-producing cells in humans (11). Inactivation of Dkk3 in the Kcnk3 null background causes extension of the hyperaldosteronemic phenotype and increased expression of Cyp11b2 in the adrenal gland to the male sex, without affecting functional zonation. These data indicate that Dkk3 is a component of the genetic circuitry regulating expression of Cyp11b2 and suggest that it may be implicated in the pathogenesis of low-renin hyperaldosteronism in humans.

Dataset Information

Human aldosterone producing cell clusters, zona glomerulosa, zona fasciculata, and zona reticularis, from adrenal glands

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