Affiliation:
1. From the Department of Cell Biology (R.C., T.M.M.), Lerner Research Institute, Cleveland Clinic College of Medicine of Case Western Reserve University; and the Department of Chemistry (X.C., R.G.S.), Case Western Reserve University, Cleveland, Ohio.
Abstract
Objective—
Mitochondrial depolarization aids platelet activation. Oxidized LDL (oxLDL) contains the medium length oxidatively truncated phospholipid hexadecyl azelaoyl-lysoPAF (HAz-LPAF) that disrupts mitochondrial function in nucleated cells, so oxLDL may augment platelet activation.
Methods and Results—
Flow cytometry showed intact oxLDL particles synergized with subthreshold amounts of soluble agonists to increase intracellular Ca
2+
, and initiate platelet aggregation and surface expression of activated gpIIb/IIIa and P-selectin. oxLDL also induced aggregation and increased intracellular Ca
2+
in FURA2-labeled cells by itself at low, although not higher, concentrations. HAz-LPAF, alone and in combination with substimulatory amounts of thrombin, rapidly increased cytoplasmic Ca
2+
and initiated aggregation. HAz-LPAF depolarized mitochondria in intact platelets, but this required concentrations beyond those that directly activated platelets. An unexpectedly large series of chemically pure truncated phospholipids generated by oxidative fragmentation of arachidonoyl-, docosahexaneoyl-, or linoleoyl alkyl phospholipids were platelet agonists. The PAF receptor, thought to effectively recognize only phospholipids with very short
sn-
2 residues, was essential for platelet activation because PAF receptor agonists blocked signaling by all these medium length phospholipids and oxLDL.
Conclusions—
Intact oxLDL particles activate platelets through the PAF receptor, and the PAF receptor responds to a far wider range of oxidized phospholipids in oxLDL than anticipated.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Cardiology and Cardiovascular Medicine
Cited by
58 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献