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Phospholipase A2 modification enhances lipoprotein(a) binding to the subendothelial matrix
J Hoover-Plow1, A Khaitan, G M Fless
1Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Department of Molecular Cardiology, The Cleveland Clinic Foundation, Ohio 44195, USA.
Thrombosis and Haemostasis
|April 8, 1998
Summary
Phospholipase A2 (PLA2) significantly increases the retention of Lipoprotein(a) [Lp(a)] in the extracellular matrix more than LDL. This suggests PLA2 modification enhances Lp(a) interactions with the matrix, impacting atherosclerosis.
Area of Science:
- Cardiovascular Biology
- Lipid Metabolism
- Atherosclerosis Research
Background:
- Lipoprotein(a) [Lp(a)] is present in atherosclerotic plaques, with distinct localization compared to LDL.
- Understanding lipoprotein interactions with the extracellular matrix is crucial for atherosclerosis research.
Purpose of the Study:
- To compare the transport, cell binding, and retention of Lp(a) and LDL in a subendothelial matrix model.
- To investigate the effect of phospholipase A2 (PLA2) on Lp(a) and LDL interactions with the extracellular matrix.
Main Methods:
- Utilized a two-compartment system with endothelial cells to model lipoprotein transport.
- Assessed lipoprotein retention and binding to matrix proteins after incubation with enzymes like PLA2.
- Investigated the role of lysine binding sites in PLA2-modified Lp(a) binding.
Main Results:
- Baseline transport and retention of Lp(a) and LDL were similar.
- PLA2 incubation caused a 4-fold increase in Lp(a) retention versus a 2-fold increase for LDL.
- PLA2 treatment enhanced Lp(a) binding to matrix proteins (fibronectin, laminin, collagen) significantly more than LDL.
Conclusions:
- PLA2 modification markedly enhances Lp(a) retention and binding to extracellular matrix components.
- The enzymatic activity of PLA2 and lysine binding sites of Lp(a) are key factors in this enhanced interaction.
- These findings highlight a mechanism by which PLA2 influences Lp(a) atherogenicity.