Leptin is a key hormone in placental physiology. It regulates trophoblast proliferation, inhibits apoptosis, stimulates protein synthesis, and regulates fetal growth and development. The mechanisms involved in the regulation of placental leptin expression

SCHANTON MALENA; BERNARDO MASKIN; A. PEREZ PEREZ; CECILIA VARONE; CAMISAY MARIA FERNANDA; ERLEJMAN ALEJANDRA

Congreso; ? LXII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC), LIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB),; 2017

Leptin is a key hormone in placental physiology. It regulates trophoblast proliferation, inhibits apoptosis, stimulates protein synthesis, and regulates fetal growth and development. The mechanisms involved in the regulation of placental leptin expression are not fully understood. Previous results from our lab demonstrated that estradiol (E2) regulates leptin expression involving genomic and non-genomic effects. In these study we aimed to analyze the effect of Sp1 and NFκB transcription factors and cAMP/PKA signaling pathways in the induction of leptin expression by E2 in human placental cells. BeWo cells cultured under standard conditions, as wells as human placental explants were used. Western blot, qRT-PCR, immunofluorescences, transfections assay with reporter constructs and expression vectors were carried out. We found that the inhibition of the NFκB factor reduced the E2 action over the leptin expression (P≤0,05), and the overexpression of the p65 subunit (Rel A) significantly increases the transcriptional activity of leptin promoter (P≤0,05). On the other hand, BeWo-Sh2 cells expressing an shRNA against ERapha protein, show no effect to E2 treatment nor with SP1 factor or with Rel A, which will suggest that theses factor requires ERalpha so it could exert its effects on E2 leptin expression. Moreover we observed that Sp1 (P≤0,05) and cAMP-PKA (P≤0,05) pathway increased leptin promoter activity, instead we can counter this effect with the pharmacological inhibitors H89 (P≤0,05) and SQ22536 (P≤0,005). Finally by immunofluorescence we observed that there is a strong correlation between the ERalpha and the p65 subunit localization. These findings suggest that leptin expression is tightly regulated and improved the comprehension of the mechanisms where by E2 regulates leptin expression and leptin function during pregnancy.Leptin is a key hormone in placental physiology. It regulates trophoblast proliferation, inhibits apoptosis, stimulates protein synthesis, and regulates fetal growth and development. The mechanisms involved in the regulation of placental leptin expression are not fully understood. Previous results from our lab demonstrated that estradiol (E2) regulates leptin expression involving genomic and non-genomic effects. In these study we aimed to analyze the effect of Sp1 and NFκB transcription factors and cAMP/PKA signaling pathways in the induction of leptin expression by E2 in human placental cells. BeWo cells cultured under standard conditions, as wells as human placental explants were used. Western blot, qRT-PCR, immunofluorescences, transfections assay with reporter constructs and expression vectors were carried out. We found that the inhibition of the NFκB factor reduced the E2 action over the leptin expression (P≤0,05), and the overexpression of the p65 subunit (Rel A) significantly increases the transcriptional activity of leptin promoter (P≤0,05). On the other hand, BeWo-Sh2 cells expressing an shRNA against ERapha protein, show no effect to E2 treatment nor with SP1 factor or with Rel A, which will suggest that theses factor requires ERalpha so it could exert its effects on E2 leptin expression. Moreover we observed that Sp1 (P≤0,05) and cAMP-PKA (P≤0,05) pathway increased leptin promoter activity, instead we can counter this effect with the pharmacological inhibitors H89 (P≤0,05) and SQ22536 (P≤0,005). Finally by immunofluorescence we observed that there is a strong correlation between the ERalpha and the p65 subunit localization. These findings suggest that leptin expression is tightly regulated and improved the comprehension of the mechanisms where by E2 regulates leptin expression and leptin function during pregnancy.