Abstract 1351: Ubiquitin Carboxyl-Terminal Esterase L1, Causative Gene of Parkinson’s Disease, Modulates Anti-Inflammatory-Mediated Vascular Remodeling
Recent analysis of human genome sequence suggests that multiple gene products regulate tissue development and organ remodeling. The goal of present study was to perform functional screening of a human endothelial cell (EC) cDNA library by Hemagglutinating Virus of Japan Envelope (HVJ-E) vector to identify novel anti-vascular remodeling factors. A7r5 (fetal rat aortic vascular smooth muscle cells (VSMC)) seeded on 96-well plates were trasnfected with HVJ-E-infused cDNA library of human umbilical venous endothelial cells and treated with platelet derived growth factor. Candidate genes were obtained from the cells of lowest proliferative population, followed with isolation of transfected genes by transformation into E.coli. This process identified an Ubiquitin carboxyl-terminal esterase L1 (UCHL1) gene that inhibited nuclear factor-kappa B (NF-κB) activity in EC and VSMC. UCHL1 has been known as causative genes of inherited Parkinson’s disease to be specifically expressed in neurons, and abnormalities in the UCHL1 are responsible for inherited Parkinson’s disease via its effects on the neuron-specific ubiquitin-proteasome system. Further study showed that the UCHL1 gene was endogenously expressed in vascular EC, VSMC, and brain tissue. Interestingly, the expression of UCHL1 was markedly induced in the neointima of the balloon-injured rat common carotid artery (CCA), and mRNA levels were increased 25-fold (P<0.05 compared with sham operated CCA). In an in vitro system, tumor necrosis factor (TNF)-α significantly increased UCHL1 gene expression in VSMC (3.6 ± 0.25 fold, P<0.0001). Over-expression of the UCHL1 gene significantly attenuated TNF-α-induced NF-κB activity in vascular cells and significantly increased inhibitor of kappa B-α (IκB-α) and eNOS protein levels in EC, possibly through the attenuation of IκB-α ubiquitination. By contrast, knockdown of UCHL1 by siRNA resulted in increased NF-κB activity. Furthermore, in vivo transfection of siRNA into rat balloon-injured CCA using ultrasound-microbubble method showed increased neointima/media areas. These data suggest that vascular remodeling is partially regulated by deubiquitination and that UCHL1 may mediate this interaction between vascular and neuronal cells.