Regulation of Pattern Recognition Receptors by the Apolipoprotein A-I Mimetic Peptide 4F

The apolipoprotein A-I (apoA-I) mimetic peptide 4F displays prominent anti-inflammatory properties, including the ability to reduce vascular macrophage content. Macrophages are a heterogenous group of cells, represented by two principal phenotypes, the classically activated M1 macrophage and an alternatively activated M2 phenotype. We recently reported that 4F favors the differentiation of human monocytes to an anti-inflammatory phenotype similar to that displayed by M2 macrophages. In the current study, microarray analysis of gene expression in monocyte-derived macrophages (MDMs) was carried out to identify inflammatory pathways modulated by 4F treatment. ApoA-I treatment of MDMs served as a control. Transcriptional profiling revealed that 4F and apoA-I modulated expression of 113 and 135 genes that regulate inflammatory responses, respectively. Cluster heat maps revealed that 4F and apoA-I induced similar changes in expression for 69 common genes. Modulation of other gene products, including STAT1 and PPARG, were unique for 4F treatment. Besides modulating inflammatory responses, 4F was found to alter gene expression in cell-to-cell signaling, cell growth/proliferation, lipid metabolism and cardiovascular system development. These data suggest that the protective effects of 4F in a number of disease states may be due to underlying changes in monocyte/macrophage gene expression. 16 samples analyzed (four 4F+LPS, four 4F, four Controls+LPS, four Controls).