Oxidized phosphatidylcholine stimulates activity of secretory phospholipase A2 group IIA and abolishes sphingomyelin-induced inhibition of the enzyme |
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| Authors: | Aleksandra A. Korotaeva Elena V. Samoilova Galina F. Piksina Nina V. Prokazova |
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| Affiliation: | 1. Copenhagen City Heart Study, Bispebjerg University Hospital, Copenhagen, Denmark;2. Department of Cardiology P, Gentofte University Hospital, Copenhagen, Denmark;3. Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark;4. Medical Research Laboratories, Department of Clinical Medicine, Aarhus University, Faculty of Health Sciences, Aarhus, Denmark;5. Clinical Institute of Surgery and Internal Medicine, University of Copenhagen, Faculty of Health Sciences, Copenhagen, Denmark;1. Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States;2. Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States;3. The Bert W. Strassburger Lipid Center, Tel Aviv University, 52621 Hashomer Tel, Israel;4. Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, 52621 Hashomer Tel, Israel;5. Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, United States;1. Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States;2. Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States;3. Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, United States;1. Department of Pharmaceutical Health Chemistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Shomachi, Tokushima 770-8505, Japan;2. Department of Medical Pharmacology, Institute of Biomedical Sciences, Tokushima University Graduate School, Shomachi, Tokushima 770-8505, Japan;3. Faculty of Pharmacy, Yasuda Women’s University, Yasuhigashi, Asaminami-ku, Hiroshima 731-0153, Japan;4. Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Kuramotocho, Tokushima 770-8503, Japan;1. Department of Physiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China;2. Department of Thoracic Surgery, First Hospital of Jilin University, Changchun 130021, China;3. Department of Surgery, China-Japan Union Hospital of Jilin University, Changchun 130033, China;4. Department of Anesthesiology, China-Japan Union Hospital of Jilin University, Changchun 130033, China;1. Department of Molecular Pharmacology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan;2. Department of Mediator and Signal Transduction Pharmacology, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan;3. Department of Anatomy, Kitasato University School of Allied Health Sciences, Sagamihara, Kanagawa, Japan;4. Department of Matrix Biology and Regenerative Medicine, Kitasato University Graduate School of Medical Sciences, Sagamihara, Kanagawa, Japan |
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| Abstract: | We have shown recently that oxidized but not native lipoproteins stimulate the activity of secretory phospholipase A2 group IIA (sPLA2(IIA)). Since oxidized lipoproteins potentially contain considerable amounts of oxidized phosphatidylcholine, we examined the effect of oxidized palmitoyl arachidonyl phosphatidylcholine (oxPC) and the competitive effects of oxPC and sphingomyelin (SM) on sPLA2(IIA) activity.OxPC either added to the assay medium as separated liposomes or incorporated in varied amounts into LDL progressively enhanced the activity of purified human sPLA2(IIA) and abolished the inhibitory effect of LDL-incorporated SM on the enzyme activity. OxPC completely abolished the inhibitory effect of SM at the oxPC/SM concentration ratio 1/2. On the other hand, SM suppressed the activating effect of oxPC in a dose-dependent manner, abolishing it almost completely at a concentration 8 times as high as that of oxPC.Thus, changes in the oxPC/SM concentration ratio in LDL may affect the regulatory mechanisms of sPLA2(IIA) activity in human blood, inducing stimulation or inhibition of the enzyme. Influence on regulation of sPLA2(IIA) activity can be useful in the development of new therapeutic approaches to the treatment of cardiovascular diseases. |
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