Lipoprotein retention on extracellular matrix (ECM) may play acentral role in atherogenesis, and a specific extracellular matrix proteoglycan, biglycan, has been implicated in lipoprotein retention in human atherosclerosis. To test whether increased cellular biglycan expression results in increased retention of lipoproteins on ECM, rat aortic smooth muscle cells (SMCs) were transduced with a human biglycan cDNA-containing retroviral vector (LBSN) or with an empty retroviral vector (LXSN). To assess the importance of biglycan's glycosaminoglycan side chains in lipoprotein retention, ECM binding studies were also performed using RASMCs transduced with a retroviral vector encoding for a mutant, glycosarninoglycan-deficient biglycan ((LBSN)-S-mut). Human biglycan mRNA and protein were confirmed in LBSN and (LBSN)-S-mut RASMCs by Northern and Western blot analyses. HDL3+E binding to SMC ECM was increased significantly (as determined by 95% confidence intervals for binding curves) for LBSN as compared to either LXSN or (LBSN)-S-mut cells; the increases for LBSN cell ECM were due primarily to an approximately 50% increase in binding sites (increased B-max)versus LXSN cell ECM and of approximately 25% versus (LBSN)-S-mut cell ECM. These results are consistent with the hypothesis that biglycan, through its glycosaminoglycan side chains, may mediate lipoprotein retention on atherosclerotic plaque ECM. (C) 2004 Elsevier Ireland Ltd. All fights reserved.
|Publication status||Published - 2004|