Effects of estradiol on HIF-1α expression and trophoblast differentiation in first trimester villous explant cultures

• Main Authors: Geum Joon Cho, Lyn Hwa Lee, Bona Lee, Jaeeun Lee, Ki-Hoon Ahn, Soon-Cheol Hong, Hai-Joong Kim, Min-Jeong Oh
• Format: Article
• Language: English
• Published: Korean Society of Obstetrics and Gynecology 2018-01-01
• Series: Obstetrics & Gynecology Science
• Subjects: estradiol; hypoxia-inducible factor-1α; trophoblasts
• Online Access: http://ogscience.org/upload/pdf/ogs-61-71.pdf

ObjectiveThe purpose of this study was to investigate the effects of estradiol on the expression of hypoxia-inducible factor (HIF)-1α and the differentiation of trophoblasts in human first trimester villous explant cultures.MethodsVillous explant cultures were established from first trimester human placentas (6–8 weeks of gestation, n=3). Normal villous tissues were explanted on Matrigel and incubated under 3% O2 tension for 5 days. To evaluate the effects of estradiol on the villous explant cultures, 1 ng/mL of estradiol was added to the culture medium. The morphological integrities and viabilities of the villous explants were monitored. Immunohistochemistry for α5 and α1 integrin was performed to assess differentiation of extravillous trophoblasts (EVTs). Expression of HIF-1α in villous explant cultures was evaluated by western blotting and densitometry.ResultsEVTs emerging from first trimester villous explant cultures formed outgrowths of cells from the distal ends and invaded the surrounding Matrigel. Exposure of villous explants to estradiol resulted in the decreased outgrowth of cells from the distal end and decreased expression of α5 integrin. However, estradiol treatment increased the invasion of villous explants into the surrounding Matrigel, concomitant with the increased expression of α1 integrin, indicating differentiation of EVTs into more invasive EVTs. On western blots, the expression of HIF-1α decreased significantly after treatment with estradiol under 3% O2 tension.ConclusionOur findings suggest that estradiol may downregulate expression of HIF-1α in placenta, which in turn promote trophoblast differentiation into invasive phenotype.