title: The PON1 M55L gene polymorphism is associated with reduced HDL-associated PAF-AH activity.
abstract: The platelet-activating factor acetylhydrolase activity associated with high density lipoprotein (HDL-PAF-AH) may substantially contribute to the antioxidant, anti-inflammatory, and overall antiatherogenic effects of HDL. Two enzymes associated with HDL express PAF-AH catalytic activity, PAF-AH itself and paraoxonase-1 (PON1). The relative contribution of these enzymes in the expression of PAF-AH activity on HDL remains to be established. We investigated whether the PON1 polymorphisms (M55L and Q192R) or the PAF-AH polymorphism V379A could affect the PAF-AH activity associated with HDL in both normolipidemic and dyslipidemic (type IIA and IIB) populations. We show for the first time that the PON1 M55L polymorphism significantly affects the HDL-PAF-AH activity in all studied groups, the PON1 L55L individuals having lower enzyme activity compared to those having 1 M and 2 M alleles. No differences in the HDL content concerning the major apolipoprotein and lipid constituents were observed between individuals carrying the PON1 L55L and those with the M55M polymorphism. Our results provide evidence that PON1 significantly contributes to the pool of HDL-PAF-AH activity in human plasma, and suggest that the low PAF-AH activity in HDL carrying the PON1 L alloenzyme may be an important factor contributing to the low efficiency of this HDL in protecting LDL against lipid peroxidation.
authors.affiliation: Department of Internal Medicine, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Anna I
authors.initials: AI
authors.lastname: Kakafika
authors.forename: Stavroula
authors.initials: S
authors.lastname: Xenofontos
authors.forename: Vasilis
authors.initials: V
authors.lastname: Tsimihodimos
authors.forename: Afroditi P
authors.initials: AP
authors.lastname: Tambaki
authors.forename: Evangelia S
authors.initials: ES
authors.lastname: Lourida
authors.forename: Rigas
authors.initials: R
authors.lastname: Kalaitzidis
authors.forename: Marios A
authors.initials: MA
authors.lastname: Cariolou
authors.forename: Moses
authors.initials: M
authors.lastname: Elisaf
authors.forename: Alexandros D
authors.initials: AD
authors.lastname: Tselepis
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D001057:Apolipoproteins E / Q000097:blood / Q000235:genetics / Q000378:metabolism; D043303:Aryldialkylphosphatase / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D015992:Body Mass Index; D008078:Cholesterol, LDL / Q000097:blood / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005838:Genotype; D006801:Humans; D006949:Hyperlipidemias / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D050356:Lipid Metabolism; D015227:Lipid Peroxidation / Q000502:physiology; D008055:Lipids / Q000097:blood / Q000235:genetics; D008075:Lipoproteins, HDL / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010741:Phospholipases A / Q000097:blood / Q000235:genetics / Q000378:metabolism; D011110:Polymorphism, Genetic; D012907:Smoking
chemical_list: D001057:Apolipoproteins E; D008078:Cholesterol, LDL; D008055:Lipids; D008075:Lipoproteins, HDL; D010741:Phospholipases A; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D043303:Aryldialkylphosphatase