Regulatory crosstalk and interference between the xenobiotic and hypoxia sensing pathways at the AhR-ARNT-HIF1α signaling node.
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the responses to toxic environmental chemicals such as TCDD or dioxin-like PCBs. To regulate gene expression, the AhR requires its binding partner, the aryl hydrocarbon receptor nuclear translocator (ARNT). ARNT is also required by the hypoxia-inducible factor-1α (HIF-1α), a crucial regulator of responses to conditions of reduced oxygen. The important role of ARNT in both the AhR and HIF-1α signaling pathways establishes a meaningful foundation for a possible crosstalk between these two vitally important signaling pathways. This crosstalk might lead to interference between the two signaling pathways and thus might play a role in the variety of cellular responses after exposure to AhR ligands and reduced oxygen availability. This review focuses on studies that have analyzed the effect of low oxygen environments and hypoxia-mimetic agents on AhR signaling and conversely, the effect of AhR ligands, with a special emphasis on PCBs, on HIF-1α signaling. We highlight studies that assess the role of ARNT, elucidate the mechanism of the crosstalk, and discuss the physiological implications for exposure to AhR-inducing compounds in the context of hypoxia.
Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA; Department of Radiation Oncology, The University of Iowa, Iowa City, IA, USA.
Sabine U
SU
Vorrink
Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA, USA; Department of Radiation Oncology, The University of Iowa, Iowa City, IA, USA. Electronic address: frederick-domann@uiowa.edu.
Frederick E
FE
Domann
D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000502:physiology*; D015687:Cell Hypoxia; D053263:Gene Regulatory Networks / Q000502:physiology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D008954:Models, Biological; D020239:Receptor Cross-Talk / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D015262:Xenobiotics / Q000378:metabolism
D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015262:Xenobiotics; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator
ARNT; Crosstalk; Environmental toxicants; Metabolism; Oxygen sensing