Functional relevance of tetraspanin CD9 in vascular smooth muscle cell injury

Vascular smooth muscle cell (VSMC) migration and proliferation are critical events in the development of neointima following vascular injury. Exogenous expression of human CD9 by CD9-adenoviral transduction led to increases in neointima. CD9 expression significantly augmented PI-3 kinase dependent Akt phosphorylation with concurrent adhesion to extracellular matrix protein fibronectin (FN). Furthermore,enhanced Akt phosphorylation was attenuated by anti-CD9 mAb7 binding. As multiple factors contribute to the regulation of VSMC phenotype, our aim was to establish whether increased CD9 expression would induce changes in the expression of other genes associated with VSMC proliferation and motility. RASM were transduced with either CD9 adenovirus or control and were plated on FN for 6hours. Cells were harvested from 3 replicate plates and total RNA from each was isolated using the TRIzol method and pooled for each CD9 and LacZ transduced RASM. RNA was sent to Genome Explorations Memphis TN for microarray analysis. Microarray analyses were done using the U230.2 rat gene chip from Affymetrix using RNA prepared from two RASM transduction experiments. Two independent microarray data sets have been generated and analyzed by comparing the filtered gene lists generated by the Affymetrix GeneChip Operating Software and looking for regulated genes common both sets of data. Analysis of this data showed the regulation of some key genes involved in the modulation of VSMC motility and proliferation.

4