alpha 1-Adrenergic stimulation of FGF-2 promoter in cardiac myocytes and in adult transgenic mouse hearts
1 Department of Physiology and 2 Department of Human Anatomy and Cell Sciences, Institute of Cardiovascular Science, St. Boniface Hospital Research Center, University of Manitoba, Winnipeg, Manitoba, Canada R3E 3J7 Fibroblast growth factor (FGF-2), a mitogenic, angiogenic, and cardioprotective age...
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Published in | American journal of physiology. Heart and circulatory physiology Vol. 276; no. 3; pp. H826 - H833 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
01.03.1999
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Online Access | Get full text |
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Summary: | 1 Department of Physiology and
2 Department of Human Anatomy and
Cell Sciences, Institute of Cardiovascular Science, St. Boniface
Hospital Research Center, University of Manitoba, Winnipeg,
Manitoba, Canada R3E 3J7
Fibroblast growth factor (FGF-2), a
mitogenic, angiogenic, and cardioprotective agent, is reported to be
released from the postnatal heart by a mechanism of transient
remodeling of the sarcolemma during contraction. This release can be
increased with adrenergic stimulation. RNA blotting was used to assess
whether FGF-2 synthesis in neonatal rat cardiomyocytes might also be
regulated by adrenergic stimulation. FGF-2 RNA levels were increased
after treatment with norepinephrine for 6 h or with the -adrenergic agonist phenylephrine for 48 h. To assess an effect on transcription, neonatal rat cardiomyocytes were transfected with a hybrid rat FGF-2
promoter/luciferase gene
( 1058FGFp. luc ) and treated
with norepinephrine or phenylephrine for 6 or 48 h, respectively. FGF-2 promoter activity was increased two- to sevenfold in an
1 -specific manner. Putative
phenylephrine-responsive elements (PEREs) were identified at positions
780 and 761 relative to a major transcription initiation
site. However, deletion analysis of
1058FGFp. luc showed that the
phenylephrine response was independent of the putative PEREs, cell
contraction, and Ca 2+ influx. In
transgenic mice expressing
1058FGFp. luc , a significant three- to sevenfold stimulation of FGF-2 promoter activity was detected
in the hearts of two independent lines 6 h after intraperitoneal administration of phenylephrine (50 mg/kg). This increase was still
apparent at 24 h but was not detected at 48 h posttreatment. Analysis
of FGF-2 mRNA in normal mouse hearts revealed accumulation of the
6.1-kb transcript at 24 h. Control of local FGF-2 synthesis at the
transcriptional level through adrenergic stimulation may be important
in the response to injury as well as in the maintenance of a healthy myocardium.
basic fibroblast growth factor; rat fibroblast growth factor-2
gene; phenylephrine; gene transfer |
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ISSN: | 0363-6135 1522-1539 |
DOI: | 10.1152/ajpheart.1999.276.3.H826 |