Vascular cell lines expressing SSAO/VAP-1: a new experimental tool to study its involvement in vascular diseases
Article first published online: 3 JAN 2012
2011 Société Française des Microscopies and Société Biologie Cellulaire de France
Biology of the Cell
Volume 103, Issue 11, pages 543–557, November 2011
How to Cite
Solé, M. and Unzeta, M. (2011), Vascular cell lines expressing SSAO/VAP-1: a new experimental tool to study its involvement in vascular diseases. Biology of the Cell, 103: 543–557. doi: 10.1042/BC20110049
- Issue published online: 3 JAN 2012
- Article first published online: 3 JAN 2012
- Received 14 April 2011/21 July 2011; accepted 5 August 2011
- cellular models;
- endothelial cells;
- primary amine oxidase (PrAO);
- semicarbazide-sensitive amine oxidase (SSAO)/vascular adhesion protein-1 (VAP-1);
- vascular pathology
Background information. PrAO (primary amine oxidase), also known as SSAO (semicarbazide-sensitive amine oxidase)/VAP-1 (vascular adhesion protein-1), is an enzyme (EC 22.214.171.124) that is highly expressed in blood vessels and participates in many cell processes, including glucose handling or inflammatory leucocyte recruitment. High activity levels of this enzyme are associated with diabetes, atherosclerosis, AD (Alzheimer's disease) or stroke, among others, thus meaning that studies concerning SSAO as a therapeutic target are becoming more frequent. However, the study of this enzyme is difficult, owing to its loss of expression in cell cultures.
Results. We have developed an endothelial cell line that stably expresses the human SSAO/VAP-1 to be used as endothelial cell model for the study of this enzyme. The transfected protein is mainly expressed as a dimer in the membrane of these cells, and we demonstrate its specific localization in the lipid rafts of endothelial cells. The protein shows levels of enzymatic activity and kinetic parameters comparable with those observed in vivo by the same cell type. The transfected SSAO/VAP-1 is also able to mediate the adhesion of leucocytes to the endothelium, a known function of this protein under inflammatory conditions. This distinctive function is not exerted by the SSAO/VAP-1 transfected protein in a smooth muscle cell line that expresses 3-fold higher protein levels. These differences have been widely reported to exist in vivo. Furthermore, using this endothelial cell model, we describe for the first time the involvement of the leucocyte-adhesion activity of SSAO/VAP-1 in the Aβ (amyloid β-peptide)-mediated pro-inflammatory effect.
Conclusions. The characterization of this new cell line shows the correct behaviour of the transfected protein and endorses the use of these cellular models for the in-depth study of the currently poorly understood functions of SSAO/VAP-1 and its involvement in the above-mentioned pathologies. This cellular model will be also useful for the evaluation of potential compounds that could modulate its activity for therapeutic purposes.