GPER membrane receptor-mediated estrogen regulation of the AMH promoter.

MARÍA DE LOS MILAGROS LOVAISA; MARIELA URRUTIA; RODOLFO REY; HELENA SCHTEINGART

Mar del Plata

Congreso; LXIII Reunion anual de la SAIC.; 2018

SAIC

Anti-Müllerian hormone (AMH) is secreted by testicular Sertoli cellsfrom the beginning of fetal life until puberty, when it is inhibited byandrogens. In conditions characterized by high estrogen levels,like Peutz-Jeghers and androgen insensitivity syndromes, AMHproduction is increased. The physiological effects of estrogens aremediated by classical nuclear receptors (ERα and ERβ), and alsoby a G protein-coupled membrane receptor (GPER). Previously,we demonstrated that estradiol (E2) mediates the increase of AMHpromoter activity in Sertoli cells by ERα. In this study we assessedwhether E2 regulates AMH promoter activity also through GPER inthe mouse pre-pubertal Sertoli cell line SMAT1.Reporter assays were performed in SMAT1 cells co-transfected witha GPER expression plasmid associated with fluorescent proteinEGFP, a firefly luciferase-associated AMH promoter plasmid, and arenilla luciferase plasmid as transfection efficiency reporter. Luciferasewas measured after incubation with 17β-E2 (10-9 M), GPER-specificagonist G1 (100 nM) or GPER antagonist G15 (100 nM) for 24hours. Results, expressed as a relative luciferase unit (RLU, mean± SEM), were compared using a paired-samples Friedman test andDunn?s multiple comparison post-test.The expression of GPER-EGFP in SMAT1 cells was confirmed byfluorescence microscopy. Basal AMH promoter activity (0.979 ±0.081 RLU) increased modestly but significantly after incubationwith E2 (1.062 ± 0.078 RLU, n=10, P=0.048) or G1 (1.109 ± 0.085RLU, n=10, P=0.022). The co-incubation with antagonist G15 didnot produce significant changes in AMH promoter activity comparedto E2 (E2: 1.062 ± 0.078 RLU, G15 + E2: 1.027 ± 0.132 RLU, n=10,P=0.227).Conclusion: Estrogen effect on AMH promoter activity is also partiallyexerted through GPER in SMAT1 cells. This suggests a mildmodulatory action of prepubertal Sertoli cells by estrogens throughGPER under physiological conditions, which could be increased insituations of hyperestrogenism.