Differential gene expression by endothelial cells in distinct angiogenic states

Angiogenesis is a complex process that can be regarded as a series of seque ntial events comprising a variety of tissue cells. The major problem when s tudying angiogenesis in vitro is the lack of a model system mimicking the v arious aspects of the process in vivo. In this study we have used two in vi tro models, each representing different and distinct aspects of angiogenesi s. Differentially expressed genes in the two culture forms were identified using the suppression subtractive hybridization technique to prepare subtra cted cDNA libraries. This was followed by a differential hybridization scre en to pick up overexpressed clones. Using comparative multiplex RT-PCR we c onfirmed the differential expression and showed differences up to 14-fold. We identified a broad range of genes already known to play an important rol e during angiogenesis like Flt1 or TIE2 Furthermore several known genes are put into the context of endothelial cell differentiation, which up to now have not been described as being relevant to angiogenesis, like NrCAM, Clau din14, BMP-6, PEA-15 and PINCH. With ADAMTS4 and hADAMTS1/METH-1 we further extended the set of matrix metalloproteases expressed and regulated by end othelial cells.