Hypoxia-inducible factor-1 mediates the biological effects of oxygen on human trophoblast differentiation through TGFβ3
Isabella Caniggia, … , Maciej Kuliszewski, Martin Post
Isabella Caniggia, … , Maciej Kuliszewski, Martin Post
Published March 1, 2000
Citation Information: J Clin Invest. 2000;105(5):577-587. https://doi.org/10.1172/JCI8316.
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Article

Hypoxia-inducible factor-1 mediates the biological effects of oxygen on human trophoblast differentiation through TGFβ3

Abstract

During early pregnancy, placentation occurs in a relatively hypoxic environment that is essential for appropriate embryonic development. Intervillous blood flow increases around 10 to 12 weeks of gestation and results in exposure of trophoblast cells to increased oxygen tension. Before this time, low oxygen appears to prevent trophoblast differentiation toward an invasive phenotype. Using human villous explants of 5–8 weeks’ gestation, we found that low oxygen tension triggered trophoblast proliferation, fibronectin synthesis, α5 integrin expression, and gelatinase A activity. These biochemical markers were barely detectable under oxic conditions. We therefore examined the placental expression of hypoxia-inducible factor-1 (HIF-1), a master regulator of oxygen homeostasis, and determined that expression of HIF-1α subunit during the first trimester of gestation parallels that of TGFβ3, an inhibitor of extravillous trophoblast differentiation. Expression of both molecules is high in early pregnancy and falls around 9 weeks of gestation, when placental pO2 levels are believed to increase. Increasing oxygen tension induced a similar decrease in expression in cultured explants. Moreover, antisense inhibition of HIF-1α expression in hypoxic explants inhibited expression of TGFβ3, arrested cell proliferation, decreased α5 expression and gelatinase A activity, and triggered biochemical markers of an invasive trophoblast phenotype such as α1 integrin and gelatinase B expression. These data suggest that the oxygen-regulated early events of trophoblast differentiation are in part mediated by TGFβ3 through HIF-1 transcription factors.

Authors

Isabella Caniggia, Homa Mostachfi, Jennifer Winter, Max Gassmann, Stephen J. Lye, Maciej Kuliszewski, Martin Post

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Antisense oligonucleotides to HIF-1α inhibit HIF-1α and TGFβ3 mRNA expre...
Antisense oligonucleotides to HIF-1α inhibit HIF-1α and TGFβ3 mRNA expression. Explants of 5–8 weeks’ gestation were treated for 5 days with 10 μM antisense oligonucleotides to HIF-1α (AS-HIF) and antisense oligonucleotides to TGFβ3 (AS-β3). Control experiments were run in parallel using either sense oligonucleotides to HIF-1α (S-HIF) and TGF-β3 (S-β3) or medium alone (C). Expression of HIF-1α and TGFβ3 mRNA was measured by low-cycle RT-PCR followed by Southern blot analysis using specific probes for HIF-1α, TGF-β3, and the control housekeeping gene β-actin. (a) Antisense HIF-1α treatment of villous explants inhibits both HIF-1α and TGFβ3 mRNA. (b) Antisense TGFβ3 treatment of villous explants inhibits TGFβ3 mRNA expression but not that of HIF-1α, whereas antisense HIF-1α exposure results in inhibition of both HIF-1α and TGFβ3 mRNA expression. (c) Bands were quantified by densitometric analysis. Shown are the changes in HIF-1α and TGFβ3 mRNA after normalization to control cultures using sense oligonucleotides. All data are expressed as the mean ± SEM of 3 separate experiments carried out in triplicate.