Browsing by Author "Fuentes Zúñiga, Cristóbal Andrés"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro
    (2013) Vecchiola Cárdenas, Andrea Paola; Lagos Arévalo, Carlos Fernando; Fuentes Zúñiga, Cristóbal Andrés; Allende, Fidel; Campino Johnson, María del Carmen; Valdivia, Carolina.; Tapia Castillo, Alejandra.; Owen, Gareth Ivor; Solari Gajardo, Sandra; Carvajal Maldonado, Cristián Andrés; Fardella B., Carlos; Ogishima, Tadashi.; Mukai, Kuniaki.
    Abstract 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.Abstract 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.
  • Thumbnail Image
    Item
    Identification of novel 11β-HSD1 inhibitors by combined ligand- and structure-based virtual screening
    (2014) Lagos Arévalo, Carlos Fernando; Vecchiola Cárdenas, Andrea Paola; Allende, Fidel; Fuentes Zúñiga, Cristóbal Andrés; Tichauer, Juan E.; Valdivia, Carolina; Solari Gajardo, Sandra; Campino Johnson, María del Carmen; Tapia-Castillo, Alejandra; Baudrand Biggs, René; Villarroel, Pia; Cifuentes, Mariana; Owen, Gareth Ivor; Carvajal, Cristian A.; Fardella B., Carlos
  • Thumbnail Image
    Item
    Usefulness and Pitfalls in Sodium Intake Estimation : Comparison of Dietary Assessment and Urinary Excretion in Chilean Children and Adults
    (2016) Campino Johnson, María del Carmen; Hill, Caroline; Baudrand Biggs, René; Martínez Aguayo, Alejandro Gregorio; Aglony Imbarack, Marlene Elizabeth; Carrasco, Carmen A.; Ferrada, Clarita; Loureiro Pérez, Carolina Andrea; Vecchiola Cárdenas, Andrea Paola; Bancalari, Rodrigo; Grob Lunecke, Francisca Andrea; Carvajal, Cristian A.; Lagos, Carlos F.; Valdivia, Carolina; Tapia-Castillo, Alejandra; Fuentes Zúñiga, Cristóbal Andrés; Mendoza, Carolina; García Bruce, Hernán; Uauy, Ricardo; Fardella B., Carlos; Campino Johnson, María del Carmen; Hill, Caroline; Baudrand Biggs, René; Martínez Aguayo, Alejandro Gregorio; Aglony Imbarack, Marlene Elizabeth; Carrasco, Carmen A.; Ferrada, Clarita; Loureiro Pérez, Carolina Andrea; Vecchiola Cárdenas, Andrea Paola; Bancalari, Rodrigo; Grob Lunecke, Francisca Andrea; Carvajal, Cristian A.; Lagos, Carlos F.; Valdivia, Carolina; Tapia-Castillo, Alejandra; Fuentes, Cristóbal A.; Mendoza, Carolina; García Bruce, Hernán; Uauy, Ricardo; Fardella B., Carlos