12-LOX catalyzes the oxidation of 2-arachidonoyl-lysolipids in platelets generating eicosanoid-lysolipids that are attenuated by iPLA 2 γ knockout.

Autor: Liu X; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110., Sims HF; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110., Jenkins CM; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110., Guan S; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110., Dilthey BG; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110., Gross RW; Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110; Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri 63110; Department of Chemistry, Washington University, Saint Louis, Missouri 63130. Electronic address: rgross@wustl.edu.
Jazyk: angličtina
Zdroj: The Journal of biological chemistry [J Biol Chem] 2020 Apr 17; Vol. 295 (16), pp. 5307-5320. Date of Electronic Publication: 2020 Mar 11.
DOI: 10.1074/jbc.RA119.012296
Abstrakt: The canonical pathway of eicosanoid production in most mammalian cells is initiated by phospholipase A 2 -mediated release of arachidonic acid, followed by its enzymatic oxidation resulting in a vast array of eicosanoid products. However, recent work has demonstrated that the major phospholipase in mitochondria, iPLA 2 γ (patatin-like phospholipase domain containing 8 (PNPLA8)), possesses sn -1 specificity, with polyunsaturated fatty acids at the sn -2 position generating polyunsaturated sn -2-acyl lysophospholipids. Through strategic chemical derivatization, chiral chromatographic separation, and multistage tandem MS, here we first demonstrate that human platelet-type 12-lipoxygenase (12-LOX) can directly catalyze the regioselective and stereospecific oxidation of 2-arachidonoyl-lysophosphatidylcholine (2-AA-LPC) and 2-arachidonoyl-lysophosphatidylethanolamine (2-AA-LPE). Next, we identified these two eicosanoid-lysophospholipids in murine myocardium and in isolated platelets. Moreover, we observed robust increases in 2-AA-LPC, 2-AA-LPE, and their downstream 12-LOX oxidation products, 12( S )-HETE-LPC and 12( S )-HETE-LPE, in calcium ionophore (A23187)-stimulated murine platelets. Mechanistically, genetic ablation of iPLA 2 γ markedly decreased the calcium-stimulated production of 2-AA-LPC, 2-AA-LPE, and 12-HETE-lysophospholipids in mouse platelets. Importantly, a potent and selective 12-LOX inhibitor, ML355, significantly inhibited the production of 12-HETE-LPC and 12-HETE-LPE in activated platelets. Furthermore, we found that aging is accompanied by significant changes in 12-HETE-LPC in murine serum that were also markedly attenuated by iPLA 2 γ genetic ablation. Collectively, these results identify previously unknown iPLA 2 γ-initiated signaling pathways mediated by direct 12-LOX oxidation of 2-AA-LPC and 2-AA-LPE. This oxidation generates previously unrecognized eicosanoid-lysophospholipids that may serve as biomarkers for age-related diseases and could potentially be used as targets in therapeutic interventions.
(© 2020 Liu et al.)
Databáze: MEDLINE
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