Gene expression profile in HUVECs before and after Angiopoietin stimulation

Angiopoietin-Tie2 sytem has been inplicated in both vascular quiescence and angiogenesis. It is unclear how these two opposing signals are regulated from the same receptor-mediated intracellular signal transduction. We have noticed that Tie2 localization upon Angiopoietin stimulation depends upon the presence or absence of cell-cell contacts. Therefore, to identify the downstream signaling of Tie2 upon Angiopoietin stimulation, we performed DNA microarray analyais using RNAs obtained from confluent human umbirical vein endothelial cells (HUVECs) or sparse HUVECs stimulated with after Angiopoietin-1. There is striking difference on gene expression profile between confluent and sparse HUVECs. Keywords: endothelial cell, angiopoietin To identify the genes in HUVECs which are upregulated or downregulated by the stimulation with Angiopoietin-1 in the presence (confluent) or absence (sparse) of cell-cell contacts, mRNAs were prepared from either confluent HUVECs or sparse HUVECs stimulated or unstimulated with 100 ng/ml COMP-Ang1 (more potent Angiopoietin-1). RNAs were obtained from HUVECs three times cultured independently three times and mixed as one RNA sample for further DNA microarray analyses. Microarray (Human Genome U133 Plus 2.0 array, Affymetrix) analyses have been performed in duplicate. Biotin labeled probes were used for the series of analyses. Hybridization and Scan were performed according to the recommendation by Affymetric. Data have been processed following the MAS 5.0 with target intensity = 100.