CAROM , a novel gene suppressing endothelial cell migration.

Hyperhomocysteinemia (HHcy), a syndrome displayed by high concentration of homocysteine (Hcy) in blood has been demonstrated as a significant risk factor for cardiovascular disease (CVD). We have shown that Hcy leaded to endothelial cells (EC) injuries through inhibition of proliferation and migration. However, the comprehensive disclosure of mechanisms accounted for Hcy mediated EC injuries are still lacking up to date. It's compelling to discover more molecules that participate in the pathogenesis of diseases involving HHcy. Through differential display screening of cDNA from Hcy stimulated cultured EC, we discovered a highly induced gene and it was identified as CAROM , which was also called FCHSD2 (FCH and double SH3 domains 2). CAROM protein belongs to Bin‐Amphiphysin‐Rvs (BAR) superfamily and specifically it is a FBAR protein since it displays Fes/CIP homology (FCH) domain on N‐terminus. Proteins in this family are usually involved in endocytosis and other cellular trafficking regulation. The function of CAROM has been poorly characterized. Three major areas were focused for this study: 1) Genomic alignment among species and prediction of interacting partners through bioinformatics; 2) Mass Spectrometry (MS) analysis for discovering interacting proteins; 3) Characterizing its role of regulating EC function. This gene displays highly conservative homology among mammalian species, with 96.5% identity of amino acids between human and mouse homologue. Information collected from multiple interactome databases showed CAROM could bind to more than thirty proteins, although most of them haven't been experimentally verified. We used samples from CAROM overexpression EC for MS analysis. Our data disclosed that CAROM complexes covered a lot proteins regulating endocytosis, vesicle trafficking and cytoskeleton dynamics. These partners included EEA1(Early Endosome Antigen 1), Filamin, Vinculin, Importin‐5, Dynein et al, suggesting it could regulate motility, migration and other cell behaviors. CAROM expression was reduced more than 80% by siRNA targeted at different regions of its transcript. With gain and loss of function strategies, we tested its potential effect on EC function. Our preliminary data showed that inhibition on EC migration by Hcy were partially reversed after CAROM downregulation, indicating its interference with EC repair after vascular injury. Further studies are needed to unveil the underlying mechanisms mediated by CAROM. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .