A targeted antioxidant reveals the importance of mitochondrial reactive oxygen species in the hypoxic signaling of HIF-1alpha.
Exposure to limiting oxygen in cells and tissues induce the stabilization and transcriptional activation of the hypoxia-inducible factor 1 alpha (HIF-1alpha) protein, a key regulator of the hypoxic response. Reactive oxygen species (ROS) generation has been implicated in the stabilization of HIF-1alpha during this response, but this is still a matter of some debate. In this study we utilize a mitochondria-targeted antioxidant, mitoubiquinone (MitoQ), and examine its effects on the hypoxic stabilization of HIF-1alpha. Our results show that under conditions of reduced oxygen (3% O(2)), MitoQ ablated the hypoxic induction of ROS generation and destabilized HIF-1alpha protein. This in turn led to an abrogation of HIF-1 transcriptional activity. Normoxic stabilization of HIF-1alpha, on the other hand, was unchanged in the presence of MitoQ suggesting that ROS were not involved. This study strongly suggests that mitochondrial ROS contribute to the hypoxic stabilization of HIF-1alpha.
Sanjuán-Pla
Alejandra
A
Unidad Mixta de Investigación Centro Nacional de Investigaciones Cardiovasculares Carlos III-Universitat de Valencia, Spain.
Cervera
Ana M
AM
Apostolova
Nadezda
N
Garcia-Bou
Remedios
R
Víctor
Víctor M
VM
Murphy
Michael P
MP
McCreath
Kenneth J
KJ
D000975:Antioxidants / Q000378:metabolism*; D015153:Blotting, Western; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D005354:Fibrosarcoma / Q000378:metabolism / Q000473:pathology; D015870:Gene Expression; D018390:Gene Targeting; D017930:Genes, Reporter; D018197:Hepatoblastoma / Q000378:metabolism / Q000473:pathology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008156:Luciferases / Q000378:metabolism; D008928:Mitochondria / Q000737:chemistry* / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*
D000975:Antioxidants; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D008156:Luciferases; D010100:Oxygen