Abstract
Mice lacking the core-clock components, cryptochrome-1 (CRY1) and cryptochrome-2 (CRY2) display a phenotype of hyperaldosteronism, due to the upregulation of type VI 3β-hydroxyl-steroid dehydrogenase (Hsd3b6), the murine counterpart to the human type I 3β-hydroxyl-steroid dehydrogenase (HSD3B1) gene. In the present study, we evaluated the role of CRY1 and CRY2 genes, and their potential interplay with HSD3B isoforms in adrenal pathophysiology in man. Forty-six sporadic aldosterone-producing adenomas (APAs) and 20 paired adrenal samples were included, with the human adrenocortical cells HAC15 used as the in vitro model. In our cohort of sporadic APAs, CRY1 expression was 1.7-fold [0.75–2.26] higher (p = 0.016), while CRY2 showed a 20% lower expression [0.80, 0.52–1.08] (p = 0.04) in APAs when compared with the corresponding adjacent adrenal cortex. Type II 3β-hydroxyl-steroid dehydrogenase (HSD3B2) was 317-fold [200–573] more expressed than HSD3B1, and is the main HSD3B isoform in APAs. Both dehydrogenases were more expressed in APAs when compared with the adjacent cortex (5.7-fold and 3.5-fold, respectively, p < 0.001 and p = 0.001) and HSD3B1 was significantly more expressed in APAs composed mainly of zona glomerulosa-like cells. Treatment with angiotensin II (AngII) resulted in a significant upregulation of CRY1 (1.7 ± 0.25-fold, p < 0.001) at 6 h, and downregulation of CRY2 at 12 h (0.6 ± 0.1-fold, p < 0.001), through activation of the AngII type 1 receptor. Independent silencing of CRY1 and CRY2 genes in HAC15 cells resulted in a mild upregulation of HSD3B2 without affecting HSD3B1 expression. In conclusion, our results support the hypothesis that CRY1 and CRY2, being AngII-regulated genes, and showing a differential expression in APAs when compared with the adjacent adrenal cortex, might be involved in adrenal cell function, and in the regulation of aldosterone production.
Highlights
Primary aldosteronism (PA), affecting 6% of the general hypertensive population [1], and up to 20% of patients referred to hypertension units [2,3], is widely recognized as the leading cause of endocrine hypertension
The expression levels of CRY1, CRY2, htyhderhouxmyla-sntetryopide Id3eβh-yhdyrdorgoexnyals-est(eHroSiDd3dBe1h)ygdernoeg.enase (HSD3B1), and HSD3B2 were determined by real-time PCR in a cohort of 46 sporadic aldosterone-producing adenomas (APAs), and 20 paired adjacent adrenal tissues
While the median expression of CRY1 was 1.7-fold [0.75–2.26] higher in APA tissues when compared with that in the adjacent adrenal cortex (p = 0.016), CRY2 showed a 20% lower expression [0.80, 0.52–1.08] in the nodule when compared with the corresponding surrounding tissue (p = 0.04) (Figure 1B)
Summary
Primary aldosteronism (PA), affecting 6% of the general hypertensive population [1], and up to 20% of patients referred to hypertension units [2,3], is widely recognized as the leading cause of endocrine hypertension. Cry-null mice displayed salt-sensitive hypertension due to chronic and autonomous aldosterone overproduction by the adrenal glands, as a consequence of the massive upregulation of type VI 3β-hydroxyl-steroid dehydrogenase (Hsd3b6), the murine counterpart to the human type I 3β-hydroxyl-steroid dehydrogenase (HSD3B1) gene [8]. Despite much knowledge being gained from the Cry-null animal model, the significance of CRY1 and CRY2 in human adrenal function and aldosterone production is still unknown. In this study we aimed to (I) evaluate the expressions of HSD3B1 and HSD3B2 in a large cohort of 46 adrenal glands, removed from patients in whom a final diagnosis of unilateral PA was achieved; and (II) investigate the expression of CRY1 and CRY2 in unilateral sporadic PA, and their roles in aldosterone production in the HAC15 human adrenocortical cell model
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