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Differentia] transcriptional regulation of endothelin‐1 by immunosuppressants FK506 and cyclosporin A
Author(s) -
Marsen Tobias A.,
Weber Frank,
Egink Guido,
Suckau Gudrun,
Baldamus Conrad A.
Publication year - 2000
Publication title -
fundamental and clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 73
eISSN - 1472-8206
pISSN - 0767-3981
DOI - 10.1111/j.1472-8206.2000.tb00422.x
Subject(s) - calcineurin , nfat , microbiology and biotechnology , reporter gene , biology , gene expression , northern blot , transcriptional regulation , luciferase , promoter , transcription factor , gene , transplantation , medicine , transfection , biochemistry
— 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 FK.506. 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.