Abreu-Rodríguez, Irene.Sánchez Silva, Rocío.Martins, Ana Paula.Soveral, Graça.Toledo-Aral, Juan José.López-Barneo, José.Echevarría, Miriam.2012-08-022012-08-022011-12-07Abreu-Rodríguez I, Sánchez Silva R, Martins AP, Soveral G, Toledo-Aral JJ, et al. Functional and Transcriptional Induction of Aquaporin-1 Gene by Hypoxia; Analysis of Promoter and Role of Hif-1α. PLoS ONE 2011; 6(12): e28385http://hdl.handle.net/10668/438Aquaporin-1 (AQP1) is a water channel that is highly expressed in tissues with rapid O(2) transport. It has been reported that this protein contributes to gas permeation (CO(2), NO and O(2)) through the plasma membrane. We show that hypoxia increases Aqp1 mRNA and protein levels in tissues, namely mouse brain and lung, and in cultured cells, the 9L glioma cell line. Stopped-flow light-scattering experiments confirmed an increase in the water permeability of 9L cells exposed to hypoxia, supporting the view that hypoxic Aqp1 up-regulation has a functional role. To investigate the molecular mechanisms underlying this regulatory process, transcriptional regulation was studied by transient transfections of mouse endothelial cells with a 1297 bp 5' proximal Aqp1 promoter-luciferase construct. Incubation in hypoxia produced a dose- and time-dependent induction of luciferase activity that was also obtained after treatments with hypoxia mimetics (DMOG and CoCl(2)) and by overexpressing stabilized mutated forms of HIF-1α. Single mutations or full deletions of the three putative HIF binding domains present in the Aqp1 promoter partially reduced its responsiveness to hypoxia, and transfection with Hif-1α siRNA decreased the in vitro hypoxia induction of Aqp1 mRNA and protein levels. Our results indicate that HIF-1α participates in the hypoxic induction of AQP1. However, we also demonstrate that the activation of Aqp1 promoter by hypoxia is complex and multifactorial and suggest that besides HIF-1α other transcription factors might contribute to this regulatory process. These data provide a conceptual framework to support future research on the involvement of AQP1 in a range of pathophysiological conditions, including edema, tumor growth, and respiratory diseases.enRNA, MessengerAquaporin 1WaterMedical Subject Headings::Chemicals and Drugs::Amino Acids, Peptides, and Proteins::Proteins::Carrier Proteins::Membrane Transport Proteins::Ion Channels::Porins::Aquaporins::Aquaporin 1Medical Subject Headings::Chemicals and Drugs::Amino Acids, Peptides, and Proteins::Proteins::DNA-Binding Proteins::Basic Helix-Loop-Helix Transcription Factors::Hypoxia-Inducible Factor 1::Hypoxia-Inducible Factor 1, alpha SubunitMedical Subject Headings::Organisms::Eukaryota::AnimalsMedical Subject Headings::Disciplines and Occupations::Natural Science Disciplines::Biological Science Disciplines::Biology::GeneticsMedical Subject Headings::Phenomena and Processes::Metabolic Phenomena::MetabolismMedical Subject Headings::Phenomena and Processes::Chemical Phenomena::Biochemical Phenomena::Molecular Structure::Binding SitesMedical Subject Headings::Phenomena and Processes::Cell Physiological Phenomena::Cell Physiological Processes::Cell Respiration::Cell HypoxiaMedical Subject Headings::Anatomy::Cells::Cells, Cultured::Cell Line::Cell Line, TumorMedical Subject Headings::Phenomena and Processes::Metabolic Phenomena::Metabolism::Biological Transport::Cell Membrane PermeabilityMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Processes::Gene Expression Regulation::Down-RegulationMedical Subject Headings::Chemicals and Drugs::Amino Acids, Peptides, and Proteins::Proteins::Transcription Factors::Basic Helix-Loop-Helix Transcription Factors::Hypoxia-Inducible Factor 1::Hypoxia-Inducible Factor 1, alpha SubunitMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Rodentia::Muridae::Murinae::MiceMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Structures::Genome::Genome Components::Genes::Gene Components::Regulatory Elements, Transcriptional::Promoter Regions, GeneticMedical Subject Headings::Phenomena and Processes::Chemical Phenomena::Biochemical Phenomena::Protein StabilityMedical Subject Headings::Chemicals and Drugs::Nucleic Acids, Nucleotides, and Nucleosides::Nucleic Acids::RNA::RNA, MessengerMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Rodentia::Muridae::Murinae::RatsMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Variation::Mutation::Sequence DeletionMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Processes::Gene Expression::Transcription, GeneticMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Processes::Gene Expression Regulation::Transcriptional ActivationMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Processes::Gene Expression Regulation::Up-RegulationMedical Subject Headings::Chemicals and Drugs::Inorganic Chemicals::Oxygen Compounds::Oxides::Waterresearch article22174795open access10.1371/journal.pone.00283851932-6203