Serial analysis of gene expression to assess the endothelial cell responseto an atherogenic stimulus

Activation of human, arterial endothelial cells (ECs) is an early event in the pathogenesis of atherosclerosis. To identify the repertoire of genes th at are differentially expressed after activation, we used serial analysis o f gene expression (SAGE) to compare the mRNA spectrum of quiescent ECs with that of ECs activated for 6 h with a strong atherogenic stimulus. SAGE met hodology generates concatenated 'tags' of 10 bp that are derived from a spe cific mRNA. About 5% of over 12 000 tags analyzed is derived from genes tha t are differentially expressed (at least 5-fold up- or downregulated). Thes e transcript tags are derived from only 56 genes, close to 1% of the total number of analyzed genes. Among these 56 differentially expressed genes are 42 known genes, including the hallmark endothelial cell activation markers interleukin 8 (IL-8), monocyte chemoattractant protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1), plasminogen activator inhibitor 1 (PAI- 1), Gro-alpha, Gro-beta and E-selectin. Differential transcription of a sel ection of the upregulated genes was confirmed by Northern blot analysis. A novel observation is the upregulation of activin beta(A) mRNA, a member of the transforming growth factor beta family. Apparent discrepancies between this novel technology and conventional methods are discussed. In conclusion , we demonstrate that for the application of SAGE, a moderate number of ana lyzed transcript tags suffices to reveal the significant alterations of EC transcription that results from a strong atherogenic stimulus. (C) 1999 Els evier Science B.V. Al rights reserved.