The intravenous anesthetics barbiturates inhibit hypoxia-inducible factor 1 activation

Hypoxia-inducible factor 1 (HIF-1) is a master transcription factor of hypoxia-induced gene expression. Anesthetics and perioperative drugs have been reported to affect HIF-1 activity. However, the effect of barbiturates on HIF-1 activity has not been reported. In this study, we investigated the effect of thiopental and thiamylal on HIF-1 activity using the neuronal SH-SY5Y cells, the non-neuronal HEK293 cells, and the macrophage-differentiated THP-1 cells. Cells were exposed to 20% or 1% O-2 conditions with or without thiopental or thiamylal treatment The cell lysate were subjected to Western blot analysis using anti-HIF-1 alpha and -HIF-1 beta antibodies. HIF-1-dependent gene expression was investigated by semi-quantitative real-time RT-PCR and luciferase assay. Hydroxylation of HIF-1 alpha protein was evaluated by in vitro pulldown assay using recombinant protein. Both thiopental and thiamylal reversibly suppressed hypoxia-induced HIF-1 activation in the neuronal and the non-neuronal cells in a dose-dependent manner. Moreover, the barbiturates inhibited lipopolysaccharide-induced HIF-1 alpha expression in THP-1 cells. The HIF-1-downstream gene expression was also inhibited by the barbiturates. HIF alpha-hydroxylases activity and HIF-1 alpha stability were not affected but the HIF-1 alpha protein neosynthesis was inhibited by the barbiturates. Our experimental results indicate that barbiturates inhibit induced HIF-1 activation and downstream genes expression. (C) 2009 Elsevier B.V. All rights reserved.