title: Differential transcriptional regulation of endothelin-1 by immunosuppressants FK506 and cyclosporin A.
abstract: Calcineurin antagonists FK506 and CsA, administered to treat organ allograft rejection, exert specific effects on renal vasoconstriction and nephrotoxicity, possibly due to endogenous vasoconstrictor release such as ET-1. We investigated contribution of FK506 and CsA on regulation of prepro ET-1 gene transcription in HUVEC. To conclude on transcriptional regulation, ET-1 mRNA levels were quantified by Northern blot analysis upon stimulation with calcineurin antagonists, and newly transcribed luciferase gene, placed under the control of the rat ET-1 promoter, was quantified by reporter gene assays, where luciferase activity reflects ET-1 promoter activation. Calcium fluorometry was employed to examine calcium dependency of ET-1 promoter-dependent gene transcription. Northern blot analysis shows differential induction of prepro ET-1 mRNA in favour of CsA over FK506. Likewise, luciferase assays demonstrate stronger ET-1 promoter-dependent stimulation of the reporter gene by CsA than by FK506. Transcription of prepro ET-1 gene upon stimulation with both calcineurin antagonists is regulated by intracellular calcium levels. Lack of extra- or intracellular calcium prevents ET-1 promoter-dependent gene transcription and ET-1 mRNA induction. These observations demonstrate that calcineurin antagonists FK506 and CsA differ in quality to induce transcription of prepro ET-1 in HUVEC via calcium-dependent nuclear signalling events. To examine the contribution of ET-1 in nephrotoxicity upon CsA and FK506 immunosuppression the availability of endothelin receptor antagonists or endothelin converting enzyme inhibitors is required.
authors.affiliation: Klinik IV für Innere Medizin, University of Cologne, Germany. tobias.marsen@uni-koeln.de
authors.forename: T A
authors.initials: TA
authors.lastname: Marsen
authors.forename: F
authors.initials: F
authors.lastname: Weber
authors.forename: G
authors.initials: G
authors.lastname: Egink
authors.forename: G
authors.initials: G
authors.lastname: Suckau
authors.forename: C A
authors.initials: CA
authors.lastname: Baldamus
mesh_terms: D015152:Blotting, Northern; D065095:Calcineurin Inhibitors; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology*; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism*; D016232:Endothelins / Q000235:genetics / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology*; D014158:Transcription, Genetic; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D065095:Calcineurin Inhibitors; D002614:Chelating Agents; D019332:Endothelin-1; D016232:Endothelins; D007166:Immunosuppressive Agents; D011498:Protein Precursors; D012333:RNA, Messenger; D004533:Egtazic Acid; D016572:Cyclosporine; C058180:5,5'-dimethyl-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate; D002118:Calcium; D016559:Tacrolimus