Objectives: 

Cerebral Cavernous Malformations (CCMs) are vascular lesions consisting of clusters of dilated thin-walled vessels lacking smooth muscle support and mostly located in the CNS. Prevalence in general population is 0.5% and symptoms include seizures, headaches and cerebral bleedings. 20% of CCMs have a genetic basis and are linked to mutations in CCM1/Krit1, CCM2/Malcavernin or CCM3/PDCD10. Very little is known about the role of CCM3/PDCD10 and that is the reason why we decided to set up the present study.

Materials: 

To achieve our goal, we downregulated CCM3/PDCD10 in a human model of endothelial cells (HCAEC) with shRNA-expressing lentiviruses. Then, we looked for transcriptional differences by gene microarrays. We also studied VEGF signaling pathway checking the levels of several downstream proteins by western blot. Moreover, we performed a vasculogenesis assay by plating the cells in a 3D-collagenous matrix.

Results: 

Regarding to gene microarrays, we found 163 genes with a significantly different pattern of expression in CCM3 knockdown cells. These genes are involved mainly in endothelial differentiation and angiogenesis. We also found that CCM3 knockdown cells are less able to respond to VEGF after serum-starvation. Besides, lack of CCM3 in endothelial cells compromises the ability of these cells to make tubes during vasculogenesis.

Conclusions: 

In conclusion, CCM3/PDCD10 seems to be a crucial gene in endothelial physiology as it is directly involved in different signaling pathways. Impairment of these pathways could be the reason why people suffering from CCMs with mutations in CCM3 show the most severe form of the disease and the worst prognosis.