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Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro
BACKGROUND: Familial hyperaldosteronism type I (FH-I) is caused by the unequal recombination between the 11beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, resulting in the generation of a CYP11B1/B2 chimeric gene and abnormal adrenal aldosterone production. Affected patients usu...
Autores principales: | , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848474/ https://www.ncbi.nlm.nih.gov/pubmed/23938178 http://dx.doi.org/10.1186/1477-7827-11-76 |
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author | Vecchiola, Andrea Lagos, Carlos F Fuentes, Cristóbal A Allende, Fidel Campino, Carmen Valdivia, Carolina Tapia-Castillo, Alejandra Ogishima, Tadashi Mukai, Kuniaki Owen, Gareth Solari, Sandra Carvajal, Cristian A Fardella, Carlos E |
author_facet | Vecchiola, Andrea Lagos, Carlos F Fuentes, Cristóbal A Allende, Fidel Campino, Carmen Valdivia, Carolina Tapia-Castillo, Alejandra Ogishima, Tadashi Mukai, Kuniaki Owen, Gareth Solari, Sandra Carvajal, Cristian A Fardella, Carlos E |
author_sort | Vecchiola, Andrea |
collection | PubMed |
description | BACKGROUND: Familial hyperaldosteronism type I (FH-I) is caused by the unequal recombination between the 11beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, resulting in the generation of a CYP11B1/B2 chimeric gene and abnormal adrenal aldosterone production. Affected patients usually show severe hypertension and an elevated frequency of stroke at a young age. Aldosterone levels rise during pregnancy, yet in pregnant women with FH-1, their hypertensive condition either remains unchanged or may even improve. The purpose of this study was to investigate in vitro whether female sex steroids modulate the activity of chimeric (ASCE) or wild type (ASWT) aldosterone synthase enzymes. METHODS: We designed an in vitro assay using HEK-293 cell line transiently transfected with vectors containing the full ASCE or ASWT cDNAs. Progesterone or estradiol effects on AS enzyme activities were evaluated in transfected cells incubated with deoxycorticosterone (DOC) alone or DOC plus increasing doses of these steroids. RESULTS: In our in vitro model, both enzymes showed similar apparent kinetic parameters (Km = 1.191 microM and Vmax = 27.08 microM/24 h for ASCE and Km = 1.163 microM and Vmax = 36.98 microM/24 h for ASWT; p = ns, Mann–Whitney test). Progesterone inhibited aldosterone production by ASCE- and ASWT-transfected cells, while estradiol demonstrated no effect. Progesterone acted as a competitive inhibitor for both enzymes. Molecular modelling studies and binding affinity estimations indicate that progesterone might bind to the substrate site in both ASCE and ASWT, supporting the idea that this steroid could regulate these enzymatic activities and contribute to the decay of aldosterone synthase activity in chimeric gene-positive patients. CONCLUSIONS: Our results show an inhibitory action of progesterone in the aldosterone synthesis by chimeric or wild type aldosterone synthase enzymes. This is a novel regulatory mechanism of progesterone action, which could be involved in protecting pregnant women with FH-1 against hypertension. In vitro, both enzymes showed comparable kinetic parameters, but ASWT was more strongly inhibited than ASCE. This study implicates a new role for progesterone in the regulation of aldosterone levels that could contribute, along with other factors, to the maintenance of an adequate aldosterone-progesterone balance in pregnancy. |
format | Online Article Text |
id | pubmed-3848474 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-38484742013-12-04 Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro Vecchiola, Andrea Lagos, Carlos F Fuentes, Cristóbal A Allende, Fidel Campino, Carmen Valdivia, Carolina Tapia-Castillo, Alejandra Ogishima, Tadashi Mukai, Kuniaki Owen, Gareth Solari, Sandra Carvajal, Cristian A Fardella, Carlos E Reprod Biol Endocrinol Research BACKGROUND: Familial hyperaldosteronism type I (FH-I) is caused by the unequal recombination between the 11beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, resulting in the generation of a CYP11B1/B2 chimeric gene and abnormal adrenal aldosterone production. Affected patients usually show severe hypertension and an elevated frequency of stroke at a young age. Aldosterone levels rise during pregnancy, yet in pregnant women with FH-1, their hypertensive condition either remains unchanged or may even improve. The purpose of this study was to investigate in vitro whether female sex steroids modulate the activity of chimeric (ASCE) or wild type (ASWT) aldosterone synthase enzymes. METHODS: We designed an in vitro assay using HEK-293 cell line transiently transfected with vectors containing the full ASCE or ASWT cDNAs. Progesterone or estradiol effects on AS enzyme activities were evaluated in transfected cells incubated with deoxycorticosterone (DOC) alone or DOC plus increasing doses of these steroids. RESULTS: In our in vitro model, both enzymes showed similar apparent kinetic parameters (Km = 1.191 microM and Vmax = 27.08 microM/24 h for ASCE and Km = 1.163 microM and Vmax = 36.98 microM/24 h for ASWT; p = ns, Mann–Whitney test). Progesterone inhibited aldosterone production by ASCE- and ASWT-transfected cells, while estradiol demonstrated no effect. Progesterone acted as a competitive inhibitor for both enzymes. Molecular modelling studies and binding affinity estimations indicate that progesterone might bind to the substrate site in both ASCE and ASWT, supporting the idea that this steroid could regulate these enzymatic activities and contribute to the decay of aldosterone synthase activity in chimeric gene-positive patients. CONCLUSIONS: Our results show an inhibitory action of progesterone in the aldosterone synthesis by chimeric or wild type aldosterone synthase enzymes. This is a novel regulatory mechanism of progesterone action, which could be involved in protecting pregnant women with FH-1 against hypertension. In vitro, both enzymes showed comparable kinetic parameters, but ASWT was more strongly inhibited than ASCE. This study implicates a new role for progesterone in the regulation of aldosterone levels that could contribute, along with other factors, to the maintenance of an adequate aldosterone-progesterone balance in pregnancy. BioMed Central 2013-08-13 /pmc/articles/PMC3848474/ /pubmed/23938178 http://dx.doi.org/10.1186/1477-7827-11-76 Text en Copyright © 2013 Vecchiola et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Vecchiola, Andrea Lagos, Carlos F Fuentes, Cristóbal A Allende, Fidel Campino, Carmen Valdivia, Carolina Tapia-Castillo, Alejandra Ogishima, Tadashi Mukai, Kuniaki Owen, Gareth Solari, Sandra Carvajal, Cristian A Fardella, Carlos E Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title | Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title_full | Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title_fullStr | Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title_full_unstemmed | Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title_short | Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
title_sort | different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848474/ https://www.ncbi.nlm.nih.gov/pubmed/23938178 http://dx.doi.org/10.1186/1477-7827-11-76 |
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