Adenovirus-mediated Overexpression of Human Transforming Growth Factor-β1 in Rat Cardiac Fibroblasts, Myocytes and Smooth Muscle Cells

Transforming growth factor-β1 (TGF-β1) is known to regulate cardiac cell function and its overexpression in the heart is thought to contribute to the development of cardiac hypertrophy and fibrosis. We wished to develop a high efficiency gene transfer method that could be used bothin vitroandin vivoand result in the overexpression of TGF-β1. For this purpose, we constructed a replication-deficient human adenovirus 5 vector encoding for human TGF-β1 and used for control purposes an adenoviruslacZvector. The adenovirus 5 construct was capable of infecting neonatal rat cardiac myocytes, fibroblasts and VSMCs. Of the three cell types, cardiac myocytes appear more susceptible to infection by the adenovirus 5 construct as assessed throughβ-galactosidase staining. Infection of cardiac fibroblasts, myocytes and VSMCs with the hTGF-β1 adenovirus leads to the expression of hTGF-β1 mRNA and enhanced levels of bioactive and total TGF-β1 protein. Infection with hTGF-β1 adenovirus also results in enhanced levels of collagen type III gene expression in VSMCs and fibroblasts whereas in cardiac myocytes it leads to increased levels for sarcomeric andβ-actin. Thus, this adenoviral vector might be used for the exploration ofin vivoeffects of altered levels of cardiac TGF-β1.