Abstract 452: Serine Carboxypeptidase 1 Mediates Vascular Remodeling by Increasing Inflammatory Cell Infiltration
In pathological vascular remodeling, contractile vascular smooth muscle cells (VSMCs) switch their phenotype to highly proliferative and migratory states leading to neointimal formation. Inflammatory cell recruitment and infiltration, which is dependent on the increased expression of adhesion molecules on the endothelial cells, is a key event to initiate SMC phenotypic modulation in vascular remodeling. Serine carboxypeptidase 1 (scpep1), a novel protease containing the putative catalytic triad (Ser-Asp-His) common to all members of the serine protease family, has been proved to be involved in vascular remodeling by promoting SMC proliferation and migration in a catalytic triad-dependent manner. To determine whether Scpep1 modulates leukocyte adhesion and infiltration, a flow-induced model of vascular remodeling was conducted in wild-type (WT) or Scpep1 knockout (KO) mice. Scpep1-null mice show a decreased number of infiltrated leukocytes into the intima and media compared to WT mice. Further, mice devoid of Scpep1 show a dramatic reduction of vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) expression in vessels in comparison with that of WT mice. Consistent with our in vivo data, the expression levels of ICAM-1 and VCAM-1 on human umbilical vein endothelial cells (HUVECs) transfected with SiRNA against Scpep1 were significantly decreased after TNF-α treatment. Taken together, these data suggest that Scpep1 may increase leukocyte extravasation by increasing the expression of VCAM-1 and ICAM-1 adhesion molecules.