Angiotensin II and III Metabolism and Effects on Steroid Production in the HAC15 Human Adrenocortical Cell Line

Abstract

Aldosterone is synthesized in the zona glomerulosa of the adrenal cortex under primary regulation by the renin-angiotensin system. Angiotensin II (A-II) acts through the angiotensin types 1 and 2 receptors (AT1R and AT2R). A-II is metabolized in different tissues by various enzymes to generate two heptapeptides A-III and angiotensin 1-7, which can then be catabolized into smaller peptides. A-II was more potent than A-III in stimulating aldosterone secretion in the adrenocortical cell line HAC15, and A-II, but not A-III, stimulated cortisol secretion. A-II stimulated mRNA expression of steroidogenic acute regulatory protein, 3β-hydroxysteroid dehydrogenase, CYP11B1, and CYP11B2, whereas A-III stimulated 3β-hydroxysteroid dehydrogenase, CYP11B1, and CYP11B2 but decreased the expression of CYP17A1 required for cortisol synthesis. The stimulation of aldosterone secretion by A-II and A-III was blocked by the AT1R receptor blocker, losartan, but not by an AT2R blocker. A-II was rapidly metabolized by the HAC15 cells to mainly to angiotensin 1-7, but not to A-III, and disappeared from the supernatant within 6 h. A-III was metabolized rapidly and disappeared within 1 h. In conclusion, A-II was not converted to A-III in the HAC15 cell and is the more potent stimulator of aldosterone secretion and cortisol of the two. A-III stimulated aldosterone secretion but not cortisol secretion.

Adipocyte-Derived Hormone Leptin Is a Direct Regulator of Aldosterone Secretion, Which Promotes Endothelial Dysfunction and Cardiac Fibrosis

“…19 The human adrenocortical cell line Pb2-Luc HAC15 cell line was provided by Dr Gomez-Sanchez (University of Mississippi) and used to detect CYP11B2 promoter activity. 20 These cells are derived from the HAC15 cell line and are stably transduced with a lentivirus in which the CYP11B2 promoter drives the expression of the secreted Gaussia luciferase enzyme. CYP11B2 promoter activity was determined by measuring luciferase activity in the experimental media with the luciferase substrate coelenterazine and a FluoStar luminometer.…”

Aldosterone biosynthesis in the human adrenal cortex and associated disorders

“…The HAC15 cell line has been demonstrated to express StAR and various kinds of steroidogenic enzymes, including CYP11A1, CYP17, CYP21, HSD3B2, CYP11B1, and CYP11B2. Ang II treatment increased the expression levels of StAR, HSD3B2, CYP11B1, and CYP11B2 by 2.4-, 1.9-, 6.9-, and 7.9-fold, respectively, in this cell line, compared to H295R cells [53]. In addition, this cell line has been reported to be responsive to Ang III and metabolites of Ang II [53].…”

“…Ang II treatment increased the expression levels of StAR, HSD3B2, CYP11B1, and CYP11B2 by 2.4-, 1.9-, 6.9-, and 7.9-fold, respectively, in this cell line, compared to H295R cells [53]. In addition, this cell line has been reported to be responsive to Ang III and metabolites of Ang II [53]. Of particular interest, aldosterone secretion was decreased by losartan alone, among the ATIII blockers employed [53].…”

“…Oki et al investigated the responsiveness of HAC15 cell line to Ang II, and reported that aldosterone levels were elevated 3.6-fold by treatment with Ang II (10 nM) for 24 h [53]. The HAC15 cell line has been demonstrated to express StAR and various kinds of steroidogenic enzymes, including CYP11A1, CYP17, CYP21, HSD3B2, CYP11B1, and CYP11B2.…”

“…In addition, this cell line has been reported to be responsive to Ang III and metabolites of Ang II [53]. Of particular interest, aldosterone secretion was decreased by losartan alone, among the ATIII blockers employed [53]. HAC15 cell line was also found to be stimulated by both Ang II and III; both were reported to bind to AT1 receptors and to stimulate acute aldosterone synthesis.…”