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Analyses of Group III Secreted Phospholipase A2 Transgenic Mice Reveal Potential Participation of This Enzyme in Plasma Lipoprotein Modification, Macrophage Foam Cell Formation, and Atherosclerosis
- Source :
- Journal of Biological Chemistry. 283:33483-33497
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- Among the many mammalian secreted phospholipase A2 (sPLA2) enzymes, PLA2G3 (group III secreted phospholipase A2) is unique in that it possesses unusual N- and C-terminal domains and in that its central sPLA2 domain is homologous to bee venom PLA2 rather than to other mammalian sPLA2s. To elucidate the in vivo actions of this atypical sPLA2, we generated transgenic (Tg) mice overexpressing human PLA2G3. Despite marked increases in PLA2 activity and mature 18-kDa PLA2G3 protein in the circulation and tissues, PLA2G3 Tg mice displayed no apparent abnormality up to 9 months of age. However, alterations in plasma lipoproteins were observed in PLA2G3 Tg mice compared with control mice. In vitro incubation of low density (LDL) and high density (HDL) lipoproteins with several sPLA2s showed that phosphatidylcholine was efficiently converted to lysophosphatidylcholine by PLA2G3 as well as by PLA2G5 and PLA2G10, to a lesser extent by PLA2G2F, and only minimally by PLA2G2A and PLA2G2E. PLA2G3-modified LDL, like PLA2G5- or PLA2G10-treated LDL, facilitated the formation of foam cells from macrophages ex vivo. Accumulation of PLA2G3 was detected in the atherosclerotic lesions of humans and apoE-deficient mice. Furthermore, following an atherogenic diet, aortic atherosclerotic lesions were more severe in PLA2G3 Tg mice than in control mice on the apoE-null background, in combination with elevated plasma lysophosphatidylcholine and thromboxane A2 levels. These results collectively suggest a potential functional link between PLA2G3 and atherosclerosis, as has recently been proposed for PLA2G5 and PLA2G10.
- Subjects :
- Genetically modified mouse
medicine.medical_specialty
Transgene
Mice, Transgenic
Lipids and Lipoproteins: Metabolism, Regulation, and Signaling
Biochemistry
Substrate Specificity
Apolipoproteins E
Mice
chemistry.chemical_compound
Phospholipase A2
In vivo
Internal medicine
medicine
Animals
Molecular Biology
Foam cell
Sequence Homology, Amino Acid
biology
Group III Phospholipases A2
Lysophosphatidylcholines
Cell Biology
Atherosclerosis
Protein Structure, Tertiary
Isoenzymes
Lipoproteins, LDL
Bee Venoms
Endocrinology
Lysophosphatidylcholine
chemistry
Phosphatidylcholines
biology.protein
Diet, Atherogenic
lipids (amino acids, peptides, and proteins)
Lipoproteins, HDL
Protein Processing, Post-Translational
Ex vivo
Foam Cells
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 283
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....ef7296e113609269a4ffe1607887361f