Tohoku J. Exp. Med., 2016 November, 240(3)

Invited Review

Expression of CYP11B2 in Aldosterone-Producing Adrenocortical Adenoma: Regulatory Mechanisms and Clinical Significance

YASUHIRO NAKAMURA,^1,2 YUTO YAMAZAKI,² YUTA TEZUKA,^3,4 FUMITOSHI SATOH^3,4 and HIRONOBU SASANO²

¹Division of Pathology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Miyagi, Japan
²Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
³Division of Nephrology, Endocrinology, and Vascular Medicine, Department of Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
⁴Division of Clinical Hypertension, Endocrinology and Metabolism, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan

Aldosterone-producing adrenocortical adenoma (APA) is responsible for the majority of cases clinically diagnosed as primary aldosteronism. Aldosterone synthase (CYP11B2) is one of the enzymes that play essential roles in aldosterone synthesis and is involved in the pathogenesis of APA. Recent studies have demonstrated that various factors and regulators influence the expression and function of CYP11B2 in APA. In particular, somatic mutations, such as gain-of-function and loss-of-function mutations, have been identified in several genes, each of which encodes a pivotal protein that affects the calcium signaling pathway, the expression of CYP11B2, and aldosterone production. The gain-of-function mutations were reported in KCNJ5 that encodes G-protein activated inward rectifier K⁺ channel 4 (Kir3.4) and in CACNA1D, encoding calcium channel, voltage-dependent, L type, alpha subunit Cav1.3. The loss-of-function mutations were found in ATP1A1 that encodes Na⁺/K⁺ ATPase α subunit and in ATP2B3, encoding Ca²⁺ ATPase. Furthermore, the aberrant expression of gonadotropin-releasing hormone receptor is associated with the overexpression of CYP11B2 and overproduction of aldosterone in APA with activating mutations in CTNNB1 encoding β-catenin. On the other hand, CYP11B2 also catalyzes the conversion of cortisol to 18-hydroxycortisol and subsequently converts 18-hydroxycortisol to 18-oxocortisol. The recent studies have identified 18-oxocortisol as an important and distinct biomarker to diagnose primary aldosteronism. In this review, we summarize the recent findings on CYP11B2 and discuss the molecular pathogenesis of APA and the clinical significance of CYP11B2.

keywords —— aldosterone-producing adrenocortical adenoma; CYP11B2; gene mutation; transcription factor; 18-oxocortisol

© 2016 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2016, 240, 183-190

Correspondence: Yasuhiro Nakamura, M.D., Ph.D., Division of Pathology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai, Miyagi 981- 8558, Japan.

e-mail: yasu-naka@patholo2.med.tohoku.ac.jp