Investigating the role of TLNRD1 in cerebral cavernous malformations and endothelial cells

Abstract

Cerebral cavernous malformations (CCM) are cerebral lesions, which affect the vasculature of the central nervous system, and they are characterized by an enlarged and leaky endothelium. The disease has an estimated prevalence of 0.1-0,5 %, however, there are currently no effective drugs available against it, and common treatment methods rely on invasive brain surgery. The CCM disease is caused by loss-of-function mutations in the key proteins of the CCM complex, which regulates endothelial cell integrity. Recently, a novel cytoskeletal regulator, TLNRD1, has been shown to have high interaction potential with the CCM complex proteins and it has been suggested to function as a possible fourth CCM protein. Until now, the function of TLNRD1 in endothelial cells and its specific interactions with the CCM proteins have remained largely unexplored. The aim of this thesis was to elucidate the specific TLNRD1-CCM complex interactions and to confirm the presence of TLNRD1 in endothelial cells and to assess its role in regulating endothelial cell junction integrity. The interaction between TLNRD1 and the CCM complex was investigated by using a mitochondrial trapping system and siRNA-mediated silencing of key CCM proteins. Secondly, the presence and role of TLNRD1 in endothelial cells was explored using a primary endothelial cell line. Together, these experiments indicate a strong interaction between TLNRD1 and CCM2, with the 4-helix domain of TLNRD1 potentially functioning as the main interaction site. Additionally, the presence of endogenous TLNRD1 was confirmed in primary endothelial cells, and preliminary data suggest that TLNRD1 may be involved in maintaining cell junction integrity in endothelial cells.