Abstract P171: Low Concentrations of Aspirin Activate Cytoprotective Signaling Pathway Genes in Human Endothelial Cells: A Gene Expression Profiling Study

Abstract

Low-dose aspirin is recommended for individuals with risk for heart disease and stroke in order to prevent thrombotic occlusive events. In addition to its well-established platelet inhibitory effects, increased expression of the antioxidant heme oxygenase-1 is considered to contribute to cardiovascular protection by aspirin. However little is known about the genome-wide changes in gene expression mediated by aspirin. In order to identify other molecular pathways and targets affected by aspirin, we investigated the global effects of aspirin treatment (3 μM and 100 μM) in vitro in human endothelial cells (Ea.hy 926) using HT-12 bead arrays (Illumina). The filtered genes were further analyzed using Ingenuity Pathway Analysis (IPA) software. We determined the gene expression profiles of endothelial cells treated with aspirin (3 μM and 100 μM) along with vehicle controls. Gene microarray analysis revealed significant upregulation of 134 genes (p <0.005 and >2 fold change) and downregulation of over 100 genes (p <0.005 and ≤0.5 fold change). Interestingly, the pattern of gene expression was similar between the two analyzed concentrations of 3 μM and 100 μM. The majority of upregulated genes were involved in gene expression, transcriptional regulation, cell-to-cell signalling and interaction and encoded transcription factors such as MAP kinases, phosphoinositide-3-kinases and cell cycle regulators (p<0.005). Several components of heterotrimeric G-proteins and G-protein-coupled receptors were also found to be upregulated which can potentially trigger phospholipase C signaling, suggesting an increase in overall intracellular second messenger signaling. In summary, our gene expression analysis suggests that aspirin at low and therapeutically relevant concentrations (3 μM) is effective in triggering cytoprotective signaling pathways some of which play a role in the regulation of heme oxygenase-1. Moreover, our study shows that low-dose aspirin results in altered expression profiles of a variety of genes. Future studies will have to address the biological and clinical relevance of these novel aspirin targets.