title: Paraoxonase 2 attenuates macrophage triglyceride accumulation via inhibition of diacylglycerol acyltransferase 1.
abstract: This study questioned the role of paraoxonase 2 (PON2) in attenuation of macrophage lipids accumulation. Mouse peritoneal macrophages (MPMs) harvested from PON2-deficient mice versus control C57BL/6 mice, look like foam cells and were larger in size and filled with lipid droplets. Macrophage triglyceride (but not cholesterol) content, biosynthesis rate, and microsomal acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) activity (not mRNA and protein) in PON2-deficient versus control MPM were all significantly increased by 4.6-, 3.6-, and 4.4-fold, respectively. Similarly, microsomal DGAT1 activity and cellular triglyceride content were significantly decreased in human PON2-transfected cells as well as upon incubation of PON2-deficient MPM with recombinant PON2. In all the above experimental systems, PON2 also decreased macrophage oxidative state. Incubation of PON2-deficient MPM with the free radicals generator 2,2'-amidinopropane hydrochloride increased cellular oxidative stress and DGAT1 activity by 2.2- and 3.4-fold, respectively, whereas incubation of microsomes from PON2-deficient MPM with superoxide dismutase decreased DGAT1 activity by 40%. We thus conclude that PON2 attenuates macrophage triglyceride accumulation and foam cell formation via inhibition of microsomal DGAT1 activity, which appears to be sensitive to oxidative state.
authors.affiliation: Lipid Research Laboratory, Technion Faculty of Medicine, Rappaport Family Institute for Research in the Medical Sciences, Rambam Medical Center, Haifa, Israel.
authors.forename: Mira
authors.initials: M
authors.lastname: Rosenblat
authors.forename: Raymond
authors.initials: R
authors.lastname: Coleman
authors.forename: Srinivasa T
authors.initials: ST
authors.lastname: Reddy
authors.forename: Michael
authors.initials: M
authors.lastname: Aviram
mesh_terms: D000818:Animals; D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D051048:Diacylglycerol O-Acyltransferase / Q000378:metabolism*; D005487:Foam Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008861:Microsomes / Q000201:enzymology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D011994:Recombinant Proteins; D014280:Triglycerides; D051048:Diacylglycerol O-Acyltransferase; D043303:Aryldialkylphosphatase