17beta-estradiol enhances leptin expression in human placental cells through genomic and nongenomic actions

YÉSICA GAMBINO; JULIETA L. MAYMÓ; ANTONIO PÉREZ-PÉREZ; JOSÉ DUEÑAS; VÍCTOR SÁNCHEZ-MARGALET; JUAN CARLOS CALVO; CECILIA L VARONE

BIOLOGY OF REPRODUCTION

Society for the Study of Reproduction

Lugar: Madison, EEUU; Año: 2010 vol. 83 p. 42 - 51

0006-3363

The process of embryo implantation and trophoblast invasion is considered the most limiting factor for the establishment of pregnancy. Leptin was originally considered as an adipocyte-derived signaling molecule for the central control of metabolism. However, leptin has been suggested to be involved in other functions during pregnancy, particularly in placenta, in which it was found to be expressed. In the present work, we have found that 17â-estradiol (E2) showed a stimulatory effect on endogenous leptin expression, when analyzed by Western blot in both BeWo choriocarcinoma cell line and normal placental explants. This effect was time and dose dependent. Maximal effect was achieved at 10 nM in BeWo cells and 1 nM in placental explants. Estradiol effect involved the estrogen receptor as its antagonist ICI 182,780 inhibits E2 induced leptin expression. Moreover, E2 treatment enhanced leptin promoter activity up to 4 times, evaluated by transient transfection with a plasmid construction containing leptin promoter region and the reporter gene luciferase. This effect was dose dependent. Deletion analysis demonstrated that a minimal promoter region between -1951 and -1847 bp is both necessary and sufficient to evidence E2 effect. Estradiol action involves estrogen receptor á as the cotransfeccion with a vector encoding the estrogen receptor á potentiated estrogen effect on leptin expression. Moreover E2 action probably involves membrane receptors too, as the treatment with estradiol-BSA complex partially enhanced leptin expression. Thereafter we determined that E2 effect could be blocked by pharmacologic inhibition of MAPK and the phosphatidylinositol 3-kinase (PI3K) pathways with 50 ìM PD98059 and 0.1ìM Wortmannin respectively. Moreover, the cotransfection of dominant negative mutants of MEK or MAPK blocked E2 induction on leptin promoter. On the other hand E2 treatment promoted ERK1/ERK2 and Akt phosphorylation in placental cells. In conclusion, we provide some evidence suggesting that E2 induces leptin expression in trophoblastic cells probably involving genomic and nongenomic action by a crosstalk between estrogen receptor á and the MAPK and PI3K signal transduction pathways.the establishment of pregnancy. Leptin was originally considered as an adipocyte-derived signaling molecule for the central control of metabolism. However, leptin has been suggested to be involved in other functions during pregnancy, particularly in placenta, in which it was found to be expressed. In the present work, we have found that 17â-estradiol (E2) showed a stimulatory effect on endogenous leptin expression, when analyzed by Western blot in both BeWo choriocarcinoma cell line and normal placental explants. This effect was time and dose dependent. Maximal effect was achieved at 10 nM in BeWo cells and 1 nM in placental explants. Estradiol effect involved the estrogen receptor as its antagonist ICI 182,780 inhibits E2 induced leptin expression. Moreover, E2 treatment enhanced leptin promoter activity up to 4 times, evaluated by transient transfection with a plasmid construction containing leptin promoter region and the reporter gene luciferase. This effect was dose dependent. Deletion analysis demonstrated that a minimal promoter region between -1951 and -1847 bp is both necessary and sufficient to evidence E2 effect. Estradiol action involves estrogen receptor á as the cotransfeccion with a vector encoding the estrogen receptor á potentiated estrogen effect on leptin expression. Moreover E2 action probably involves membrane receptors too, as the treatment with estradiol-BSA complex partially enhanced leptin expression. Thereafter we determined that E2 effect could be blocked by pharmacologic inhibition of MAPK and the phosphatidylinositol 3-kinase (PI3K) pathways with 50 ìM PD98059 and 0.1ìM Wortmannin respectively. Moreover, the cotransfection of dominant negative mutants of MEK or MAPK blocked E2 induction on leptin promoter. On the other hand E2 treatment promoted ERK1/ERK2 and Akt phosphorylation in placental cells. In conclusion, we provide some evidence suggesting that E2 induces leptin expression in trophoblastic cells probably involving genomic and nongenomic action by a crosstalk between estrogen receptor á and the MAPK and PI3K signal transduction pathways.