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Pignatti E, Kollar J, Hafele E, Schuster D, Steele RE, Vogt B, Schumacher C, Groessl M. Structural and clinical characterization of CYP11B2 inhibition by dexfadrostat phosphate. J Steroid Biochem Mol Biol 2023; 235:106409. [PMID: 37827219 DOI: 10.1016/j.jsbmb.2023.106409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/06/2023] [Accepted: 10/08/2023] [Indexed: 10/14/2023]
Abstract
Aldosterone synthase (CYP11B2) represents a promising drug target because its genetic dysregulation is causally associated with cardiovascular disease, its autonomous activity leads to primary aldosteronism, and its deficiency leads to salt wasting syndromes. The serendipitous discovery that the dextro-rotatory stereoisomer of the racemic aromatase (CYP19A1) inhibitor CGS16949A mediates potent CYP11B2 inhibition led to the purification and clinical development of dexfadrostat phosphate. To characterize the pharmacophore of dexfadrostat phosphate, structure-based enzyme coordination with CYP11B2, CYP11B1 and CYP19A1 was combined with steroid turnover upon in vitro and clinical treatment. Dexfadrostat, but not its 5S-enantiomer (5S-fadrozole), precisely coordinates with the catalytic heme moiety in the space of the CYP11B2 substrate binding pocket forming a tight and stable complex. Conversely, neither rigid nor flexible docking led to a plausible coordination geometry for dexfadrostat in steroid 11β-hydroxylase (CYP11B1 - orthologue to CYP11B2) or in CYP19A1. The inhibitory preference of dexfadrostat was confirmed in vitro using an adrenal cortex-derived cell line. Dexfadrostat phosphate treatment of healthy subjects in the context of a clinical phase 1 study led to a dose-dependent decrease in urinary aldosterone secretion, accompanied by an increase in urinary corticosterone and deoxycorticosterone metabolites. Increased urinary corticosterone metabolites are indicative of CYP11B2 (18-oxidase) inhibition with clinical features reminiscent of patients with inborn corticosterone methyloxidase type II deficiency. An off-target effect on CYP19A1 was not observed as indicated by no clinical changes in testosterone and estradiol levels. Therefore, dexfadrostat exhibits the ideal structural features for binding and catalytic inhibition of CYP11B2 but not CYP11B1. Clinically, treatment with dexfadrostat phosphate leads to suppression of aldosterone levels by inhibiting predominantly one or both final CYP11B2-mediated reactions.
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Affiliation(s)
- Emanuele Pignatti
- Department of Pediatric Endocrinology, Diabetology and Metabolism, University Hospital Inselspital, University of Bern, 3010 Bern, Switzerland; Department for BioMedical Research, University Hospital Inselspital, University of Bern, 3010 Bern, Switzerland.
| | - Jakub Kollar
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Evelyn Hafele
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Daniela Schuster
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University, 5020 Salzburg, Austria
| | | | - Bruno Vogt
- Department of Nephrology and Hypertension, University Hospital Inselspital, University of Bern, 3010 Bern, Switzerland
| | | | - Michael Groessl
- Department for BioMedical Research, University Hospital Inselspital, University of Bern, 3010 Bern, Switzerland; Department of Nephrology and Hypertension, University Hospital Inselspital, University of Bern, 3010 Bern, Switzerland
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