Dexamethasone impairs hypoxia-inducible factor-1 function

AE Wagner, G Huck, DP Stiehl, W Jelkmann… - Biochemical and …, 2008 - Elsevier
AE Wagner, G Huck, DP Stiehl, W Jelkmann, T Hellwig-Bürgel
Biochemical and biophysical research communications, 2008Elsevier
Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription-factor composed of α-and
β-subunits. HIF-1 is not only necessary for the cellular adaptation to hypoxia, but it is also
involved in inflammatory processes and wound healing. Glucocorticoids (GC) are
therapeutically used to suppress inflammatory responses. Herein, we investigated whether
GC modulate HIF-1 function using GC receptor (GR) possessing (HepG2) and GR deficient
(Hep3B) human hepatoma cell cultures as a model systems. Dexamethasone (DEX) …
Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription-factor composed of α- and β-subunits. HIF-1 is not only necessary for the cellular adaptation to hypoxia, but it is also involved in inflammatory processes and wound healing. Glucocorticoids (GC) are therapeutically used to suppress inflammatory responses. Herein, we investigated whether GC modulate HIF-1 function using GC receptor (GR) possessing (HepG2) and GR deficient (Hep3B) human hepatoma cell cultures as a model systems. Dexamethasone (DEX) treatment increased HIF-1α levels in the cytosol of HepG2 cells, while nuclear HIF-1α levels and HIF-1 DNA-binding was reduced. In addition, DEX dose-dependently lowered the hypoxia-induced luciferase activity in a reporter gene system. DEX suppressed the hypoxic stimulation of the expression of the HIF-1 target gene VEGF (vascular endothelial growth factor) in HepG2 cultures. DEX did not reduce hypoxically induced luciferase activity in HRB 5 cells, a Hep3B derivative lacking GR. Transient expression of the GR in HRB 5 cells restored the susceptibility to DEX. Our study discloses the inhibitory action of GC on HIF-1 dependent gene expression, which may be important with respect to the impaired wound healing in DEX-treated patients.
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