Cardiac-Specific Gene Expression Facilitated by an Enhanced Myosin Light Chain Promoter

Background: Adenoviral gene transfer has been shown to be effective in cardiac myocytes in vitro and in vivo. A major limitation of myocardial gene therapy is the extracardiac transgene expression. Methods: To minimize extracardiac gene expression, we have constructed a tissue-specific promoter for...

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Main Authors: Wolfgang Boecker, Oliver Y. Bernecker, Joseph C. Wu, Xinsheng Zhu, Tomohiro Sawa, Luanda Grazette, Anthony Rosenzweig, Federica del Monte, Ulrich Schmidt, Roger J. Hajjar
Format: Article
Language:English
Published: SAGE Publishing 2004-04-01
Series:Molecular Imaging
Online Access:https://doi.org/10.1162/15353500200404103
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Summary:Background: Adenoviral gene transfer has been shown to be effective in cardiac myocytes in vitro and in vivo. A major limitation of myocardial gene therapy is the extracardiac transgene expression. Methods: To minimize extracardiac gene expression, we have constructed a tissue-specific promoter for cardiac gene transfer, namely, the 250-bp fragment of the myosin light chain-2v (MLC-2v) gene, which is known to be expressed in a tissue-specific manner in ventricular myocardium followed by a luciferase (luc) reporter gene (Ad.4 × MLC 250 .Luc). Rat cardiomyocytes, liver and kidney cells were infected with Ad.4 × MLC.Luc or control vectors. For in vivo testing, Ad.4 × MLC 250 .Luc was injected into the myocardium or in the liver of rats. Kinetics of promoter activity were monitored over 8 days using a cooled CCD camera. Results: In vitro: By infecting hepatic versus cardiomyocyte cells, we found that the promoter specificity ratio (luc activity in cardiomyocytes per liver cells) was 20.4 versus 0.9 (Ad.4 × MLC 250 .Luc vs. Ad.CMV). In vivo: Ad.4 × MLC 250 .Luc significantly reduced luc activity in liver (38.4-fold), lung (16.1-fold), and kidney (21.8-fold) versus Ad.CMV ( p = .01); whereas activity in the heart was only 3.8-fold decreased. The gene expression rate of cardiomyocytes versus hepatocytes was 7:1 (Ad.4 × MLC.Luc) versus 1:1.4 (Ad.CMV.Luc). Discussion: This new vector may be useful to validate therapeutic approaches in animal disease models and offers the perspective for selective expression of therapeutic genes in the diseased heart.
ISSN:1536-0121