Suppression subtractive hybridization identifies distinctive expression markers for coronary and internal mammary arteries.

OBJECTIVE We sought to identify differentially expressed genes in the athero-prone coronary artery and athero-resistant internal mammary arteries. METHODS AND RESULTS Using suppressive subtraction hybridization, we generated reciprocal cDNA collections of representative mRNAs specific to porcine coronary arteries versus porcine mammary arteries. We screened 1000 suppressive subtraction hybridization cDNA clones by dot blot array and sequenced 600 of those showing the most marked expression differences. Northern blot, in situ hybridization, and immunostaining confirmed the differential gene expression patterns identified by the dot blot arrays. Genes associated with mammary arteries included claudin-10 and h-cadherin, which are genes associated with tight junctions and intermediate junctions. In contrast, genes associated with proatherosclerotic processes, such as lipid retention and metabolism, inflammation, and cell growth, were preferentially expressed in coronary arteries. CONCLUSIONS Normal coronary arteries have gene expression program that is significantly different than internal mammary arteries. These differences may partly explain the resistance of coronary arteries and internal mammary arteries to atherosclerosis.