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  1. Azizan EA, Brown MJ
    Curr Opin Endocrinol Diabetes Obes, 2016 06;23(3):209-17.
    PMID: 26992195 DOI: 10.1097/MED.0000000000000255
    PURPOSE OF REVIEW: Aldosterone regulation in the adrenal plays an important role in blood pressure. The commonest curable cause of hypertension is primary aldosteronism. Recently, mutations in novel genes have been identified to cause primary aldosteronism. Elucidating the mechanism of action of these genetic abnormalities may help understand the cause of primary aldosteronism and the physiological regulation of aldosterone in the zona glomerulosa.

    RECENT FINDINGS: KCNJ5, ATP1A1, ATP2B3, CACNA1D, CTNNB1, and CACNA1H mutations are causal of primary aldosteronism. ARMC5 may cause bilateral lesions resulting in primary aldosteronism.LGR5, DACH1, and neuron-specific proteins are highly expressed in the zona glomerulosa and regulate aldosterone production.

    SUMMARY: Most mutations causing primary aldosteronism are in genes encoding cation channels or pumps, leading to increased calcium influx. Genotype-phenotype analyses identified two broad subtypes of aldosterone-producing adenomas (APAs), zona fasciculata-like and zona glomerulosa-like, and the likelihood of under-diagnosed zona glomerulosa-like APAs because of small size. Zona fasciculata-like APAs are only associated with KCNJ5 mutations, whereas zona glomerulosa-like APAs are associated with mutations in ATPase pumps, CACNA1D, and CTNNB1. The frequency of APAs, and the multiplicity of causal mutations, suggests a pre-existing drive for these mutations. We speculate that these mutations are selected for protecting against tonic inhibition of aldosterone in human zona glomerulosa, which express genes inhibiting aldosterone production.

    Matched MeSH terms: Hyperaldosteronism/genetics*
  2. Zhou J, Lam B, Neogi SG, Yeo GS, Azizan EA, Brown MJ
    Hypertension, 2016 12;68(6):1424-1431.
    PMID: 27777363
    Primary aldosteronism is present in ≈10% of hypertensives. We previously performed a microarray assay on aldosterone-producing adenomas and their paired zona glomerulosa and fasciculata. Confirmation of top genes validated the study design and functional experiments of zona glomerulosa selective genes established the role of the encoded proteins in aldosterone regulation. In this study, we further analyzed our microarray data using AmiGO 2 for gene ontology enrichment and Ingenuity Pathway Analysis to identify potential biological processes and canonical pathways involved in pathological and physiological aldosterone regulation. Genes differentially regulated in aldosterone-producing adenoma and zona glomerulosa were associated with steroid metabolic processes gene ontology terms. Terms related to the Wnt signaling pathway were enriched in zona glomerulosa only. Ingenuity Pathway Analysis showed "NRF2-mediated oxidative stress response pathway" and "LPS (lipopolysaccharide)/IL-1 (interleukin-1)-mediated inhibition of RXR (retinoid X receptor) function" were affected in both aldosterone-producing adenoma and zona glomerulosa with associated genes having up to 21- and 8-fold differences, respectively. Comparing KCNJ5-mutant aldosterone-producing adenoma, zona glomerulosa, and zona fasciculata samples with wild-type samples, 138, 56, and 59 genes were differentially expressed, respectively (fold-change >2; P<0.05). ACSS3, encoding the enzyme that synthesizes acetyl-CoA, was the top gene upregulated in KCNJ5-mutant aldosterone-producing adenoma compared with wild-type. NEFM, a gene highly upregulated in zona glomerulosa, was upregulated in KCNJ5 wild-type aldosterone-producing adenomas. NR4A2, the transcription factor for aldosterone synthase, was highly expressed in zona fasciculata adjacent to a KCNJ5-mutant aldosterone-producing adenoma. Further interrogation of these genes and pathways could potentially provide further insights into the pathology of primary aldosteronism.
    Matched MeSH terms: Hyperaldosteronism/genetics*
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