17-β Estradiol Attenuates Hypoxic Induction of HIF-1α and Erythropoietin in Hep3B Cells
- 1 July 2004
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Cardiovascular Pharmacology
- Vol. 44 (1), 93-100
- https://doi.org/10.1097/00005344-200407000-00013
Abstract
Hypoxia inducible factor-1 (HIF-1) is a heterodimeric transcription factor that regulates expression of several hypoxia-inducible genes, including erythropoietin (EPO), by binding to hypoxia response elements (HREs) in their promoters/enhancers. Previously, we have shown that 17-β estradiol (E2-β) attenuates hypoxic induction of EPO in rats. We hypothesized that this response is mediated by E2-β-induced attenuation of HIF-1α activity/expression. To test this hypothesis, we performed reporter gene assays in Hep3B cells to assess E2-β effects on hypoxia-induced activity of a reporter gene driven by the HRE from a cloned EPO-enhancer element. Immunocytochemistry and Western blots were additionally used to determine effects of E2-β on hypoxic increases in HIF-1α and EPO immunoreactivity. Finally, we examined potential influences of E2-β on HIF-1α mRNA levels by real-time PCR. Consistent with our hypothesis, E2-β (100 pM) inhibited hypoxic increases in HRE-mediated reporter gene activity. Furthermore, the estrogen-receptor antagonist ICI 182,780 (25 μM) eliminated these inhibitory effects of E2-β. E2-β similarly attenuated hypoxic induction of both EPO and HIF-1α protein in an estrogen-receptor dependent manner, but was without effect on HIF-1α mRNA expression. These findings suggest a role for E2-β to attenuate EPO expression by interfering with hypoxic increases in HIF-1α protein through an estrogen receptor-dependent mechanism.Keywords
This publication has 28 references indexed in Scilit:
- 17β-Estradiol decreases hypoxic induction of erythropoietin gene expressionAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2002
- Estradiol attenuates hypoxia-induced pulmonary endothelin-1 gene expressionAmerican Journal of Physiology-Lung Cellular and Molecular Physiology, 2002
- Estradiol-induced attenuation of pulmonary hypertension is not associated with altered eNOS expression.American Journal of Physiology-Lung Cellular and Molecular Physiology, 2001
- Hypoxia Regulates Expression of the Endothelin-1 Gene through a Proximal Hypoxia-Inducible Factor-1 Binding Site on the Antisense StrandBiochemical and Biophysical Research Communications, 1998
- Activation of Hypoxia-inducible Transcription Factor Depends Primarily upon Redox-sensitive Stabilization of Its α SubunitPublished by Elsevier BV ,1996
- The oxygen sensor that controls EPO production: facts and fanciesjpme, 1995
- Characterization of hypoxia-responsive enhancer in the human erythropoietin gene shows presence of hypoxia-inducible 120-Kd nuclear DNA-binding protein in erythropoietin-producing and nonproducing cellsBlood, 1993
- A nuclear factor induced by hypoxia via de novo protein synthesis binds to the human erythropoietin gene enhancer at a site required for transcriptional activation.Molecular and Cellular Biology, 1992
- The regulated expression of erythropoietin by two human hepatoma cell lines.Proceedings of the National Academy of Sciences, 1987
- Polycythemia and the acute hypoxic response in awake rats following chronic hypoxiaJournal of Applied Physiology, 1983