gms | German Medical Science

Objective: CCMs affect around 0.5% populations and present as recurrent headaches, seizures and hemorrhagic stroke. The mutation of ccm1, ccm2 and ccm3 genes has been frequently reported in familial CCMs. However, the expression profile, and particularly the functions of these genes remain largely unknown. The present work aimed to study the expression of ccm1, cccm2 and ccm3 genes in purified endothelial cells (ECs) from CCMs, and furthermore, to explore the potential functions of these genes.

Methods: ECs were isolated, purified and cultured from the fresh surgical specimens of CCMs (CCM-ECs) and epilepsies (Epi-ECs, as controls). The expression of ccm1, ccm2 and ccm3 genes was detected by real-time PCR. The response of these two types of ECs to apoptotic stimuli was compared after exposure to 50 nM staurosporine (STS), a well accepted apoptosis inducer. The proliferation profile of ECs was checked after ccm1 gene silencing using siRNA technique.

Results: Real-time PCR revealed a 2-fold lower level of ccm1 gene in CCM-ECs in comparison to the Epi-ECs (p<0.05), whereas ccm2 gene was similarly expressed in CCM-ECS and in Epi-ECs. Interestingly, around 3-fold higher expression of ccm3 genes was detected in CCM-ECs than that of Epi-ECs. Of note, CCM-ECs appeared more resistant to apoptotic damage induced by STS compared with Epi-ECs (p<0.001), which may be associated with the higher expression of ccm3 in CCM-ECs. Furthermore, ccm1 gene silencing resulted in a significant reduction of endothelial proliferation (p<0.001).

Conclusions: We reported here for the first time a distinct expression pattern of ccm1, ccm2 and ccm3 genes in pure ECs of CCMs. Ccm1 gene seems to be involved in the regulation of EC proliferation, whereas ccm3 gene likely plays a critical role in anti-apoptosis. These findings may advance our understanding of these genes and support the notion that impaired expression of these genes may potentially contribute to the pathogenesis of CCM.