Paper Report for: Mitsios_2006_Arterioscler.Thromb.Vasc.Biol_26_1907
Reference
Title: Human platelets secrete the plasma type of platelet-activating factor acetylhydrolase primarily associated with microparticles Mitsios JV, Vini MP, Stengel D, Ninio E, Tselepis AD Ref: Arterioscler Thromb Vasc Biol, 26:1907, 2006 : PubMed
OBJECTIVE: Platelet-activating factor acetylhydrolase (PAF-AH) expresses a Ca2+-independent phospholipase A2 activity and hydrolyzes platelet-activating factor as well as oxidized phospholipids. Two major types of PAF-AH have been described: the plasma type, which is associated with lipoproteins, and the intracellular type II PAF-AH. METHODS AND RESULTS: We investigated the type(s) of PAF-AH expressed in human platelets as well as the mechanism and the enzyme type secreted from platelets during activation. The majority of the enzyme activity (75.1+/-14.3% of total) is found in the cytosol, whereas 24.9+/-7.3% is associated with the membranes. Immunofluorescence microscopy studies and Western blotting analysis showed that platelets contain the plasma type as well as the intracellular type II PAF-AH. Furthermore, platelets contain high levels of the mRNA of plasma PAF-AH, whereas only a small quantity of the type II PAF-AH mRNA was detected. On activation, platelets secrete the plasma type of PAF-AH mainly associated with platelet-derived microparticles (PMPs). The enzyme activity was also detected on circulating PMPs in plasma from normolipidemic healthy subjects. CONCLUSIONS: This is the first indication that in addition to lipoproteins, PAF-AH in human plasma is carried by PMPs, suggesting that the PMP-associated PAF-AH may play a role in the dissemination of biological activities mediated by these particles.
        
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Mitsios JV, Vini MP, Stengel D, Ninio E, Tselepis AD (2006) Human platelets secrete the plasma type of platelet-activating factor acetylhydrolase primarily associated with microparticles Arterioscler Thromb Vasc Biol26: 1907-13
Mitsios JV, Vini MP, Stengel D, Ninio E, Tselepis AD (2006) Arterioscler Thromb Vasc Biol26: 1907-13