title: Hypoxia regulates the expression of the adrenomedullin and HIF-1 genes in cultured HL-1 cardiomyocytes.
abstract: Adrenomedullin (AM) is a hypotensive protein expressed in a variety of cells and tissues. We observed previously that the expression of the adrenomedullin gene increases substantially in the developing rat heart and in cultured adult rat ventricular cardiac myocytes in response to hypoxia as a function of time. An adrenomedullin promoter-luciferase reporter construct was used to show that this increase in adrenomedullin mRNA resulted from increased transcription in response to hypoxia. We report here additional evidence documenting that this hypoxia-induced transcription of the adrenomedullin gene is regulated by the hypoxia-inducible factor-1 (HIF-1) transcription factor. We used Northern blot analysis to show an increase in the levels of AM and HIF-1alpha mRNA but not HIF-1beta mRNA in the HL-1 cardiac myocyte cell line in response to hypoxia. Furthermore, Western blot analysis revealed that the levels of both HIF-1alpha and HIF-1beta protein increased under hypoxic conditions. Data from electrophoretic mobility shift assays indicate that the heterodimeric HIF-1 complex binds to the HIF-1-responsive elements. Combined data from these studies demonstrate that the AM gene is regulated by hypoxia-responsive elements localized in the AM promoter region.
authors.affiliation: Department of Biochemistry and Molecular Biology, Louisiana State University Health Science Center, New Orleans, Louisiana, 70112, USA.
authors.forename: S V
authors.initials: SV
authors.lastname: Nguyen
authors.forename: W C
authors.initials: WC
authors.lastname: Claycomb
mesh_terms: D053607:Adrenomedullin; D000818:Animals; D001483:Base Sequence; D015687:Cell Hypoxia / Q000235:genetics*; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000235:genetics; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008156:Luciferases / Q000235:genetics; D008222:Lymphokines / Q000235:genetics; D051379:Mice; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; D016228:Endothelial Growth Factors; C497443:Hif1a protein, mouse; C497444:Hif1a protein, rat; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008222:Lymphokines; D009687:Nuclear Proteins; D010455:Peptides; D012333:RNA, Messenger; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D053607:Adrenomedullin; D008156:Luciferases