Abstract 1720: Transcript Levels of Genes Involved in Receptor and Inflammasome-Mediated Initiation Pathways of Apoptosis are Elevated During Lesion Progression of Human Atherosclerosis
To identify novel regulators of plaque progression we evaluated whole genome gene expression profiles of early and advanced human carotid atherosclerotic lesions. Expression profiles of early and advanced lesions were compared within the same patient, to reduce the effect of confounders such as medication and age. After microscopic classification, RNA isolation and quality control, RNA from 8 paired samples from 4 autopsy donors was used and hybridized in duplicate to the HGU133 2.0 Plus Array (Affymetrix, Santa Clara, CA). Statistical analysis was performed using the Statistical Analysis of Micro array (SAM) method. After correction for multiple testing, 524 genes with significant differential transcript levels were identified. Pathway analysis with Ingenuity and GeneGO revealed a set of apoptosis initiating genes with modest but coordinated upregulated expression levels in advanced lesions. These genes were involved in receptor mediated (TRAIL (1,7↑), CD40 (1,7↑), Casp8 (1,5↑) CFLAR (1,4↑)), or “inflammasome” mediated initiation of apoptosis (Casp1(1,9↑), Pycard (3,5↑), CARD8 (1,5↑), CARD6 (1,6↑), FkBP1A (1,2↑) or both pathways (HSXIAPAF1 (1,3↑), BID (1,6↑)). Real time PCR validation on a series of independent carotid samples confirmed the upregulation of Pycard (2.4 ↑), Casp1 (2.7 ↑), CARD 6 (1.7 ↑), TRAIL (1.5 ↑), CARD8 (1.8 ↑), CFLAR (1.1 ↑), Casp8(1.5 ↑), HSXIAPAF1 (1,6 ↑), FkBP1A (1,6 ↑) and CD40 (1,2 ↑). Immunohistochemical evaluation of eight of the corresponding proteins showed a prominent staining of atherosclerotic macrophages. In addition, intimal and medial smooth muscle cells and endothelial cells stained positive. In conclusion, intrapatient gene expression profiling of early and advanced human carotid atherosclerotic lesions identified a coordinated increased expression of a set of genes involved in receptor and inflammasome-mediated apoptosis during plaque progression. These data opens the perspective to modulate the initiation of apoptosis as a possible therapeutic intervention.