Gene Expression Profile of Mouse Myocardium with Transgenic Overexpression of Adenosine A1 Receptors

Transgenic mice with cardiac-specific overexpression of adenosine A1 receptors have demonstrated metabolic and functional tolerance to myocardial ischemia. We utilized cDNA microarrays to test the hypothesis that the cardioprotective mechanism(s) of A1 overexpression involve(s) altered gene expression. Total RNA extracted from the left ventricles from A1 transgenic (n=4) and wild-type (n=6) mice was hybridized to Affymetrix murine U74A chips. Comparison of RNA expression levels in transgenic to wild-type myocardium revealed approximately 636 known genes with expression significantly altered by greater than 25%. We observed increased expressions of genes including NADH dehydrogenase, the GLUT4 glucose transporter, Na/K ATPase, sarcolemmal KATP channels, and Bcl-xl in A1 receptor overexpressing hearts. We also observed decreased expression of pro-apoptotic genes including a 50% reduction in message level of caspase-8. Protein expression of GLUT4 and caspase-8 was also altered comparable to the differences in gene expression. These data illustrate genes with chronically altered patterns of expression in A1 transgenic mouse myocardium that may be related to adenosine receptor overexpression-mediated cardioprotection.