Hydrolysis of glycerophosphocholine epoxides by human group IIA , V, and X secretory phospholipases A 2

Phospholipases A2 (PLA2s) catalyze hydrolysis of the sn-2 substituent from glycerophospholipids to yield a free fatty acid (i.e., arachidonic acid), which can be metabolized to pro- or anti-inflammatory eicosanoids. Macrophages modulate inflammatory responses and are affected by Ca2+-independent phospholipase A2 (PLA2)β (iPLA2β). Here, we assessed the link between iPLA2β-derived lipids (iDLs) and macrophage polarization. Macrophages from WT and KO (iPLA2β−/−) mice were classically M1 pro-inflammatory phenotype activated or alternatively M2 anti-inflammatory phenotype activated, and eicosanoid production was determined by ultra-performance LC ESI-MS/MS. As a genotypic control, we performed similar analyses on macrophages from RIP.iPLA2β.Tg mice with selective iPLA2β overexpression in β-cells. Compared with WT, generation of select pro-inflammatory prostaglandins (PGs) was lower in iPLA2β−/−, and that of a specialized pro-resolving lipid mediator (SPM), resolvin D2, was higher; both changes are consistent with the M2 phenotype. Conversely, macrophages from RIP.iPLA2β.Tg mice exhibited an opposite landscape, one associated with the M1 phenotype: namely, increased production of pro-inflammatory eicosanoids (6-keto PGF1α, PGE2, leukotriene B4) and decreased ability to generate resolvin D2. These changes were not linked with secretory PLA2 or cytosolic PLA2α or with leakage of the transgene. Thus, we report previously unidentified links between select iPLA2β-derived eicosanoids, an SPM, and macrophage polarization. Importantly, our findings reveal for the first time that β-cell iPLA2β-derived signaling can predispose macrophage responses. These findings suggest that iDLs play critical roles in macrophage polarization, and we posit that they could be targeted therapeutically to counter inflammation-based disorders.

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The molecular basis of phosphatidylcholine preference of human group-V phospholipase A2

Biochemical Journal ◽

10.1042/bj3480643 ◽

2000 ◽

Vol 348 (3) ◽

pp. 643-647 ◽

Cited By ~ 11

Author(s):

Kwang Pyo KIM ◽

Sang Kyou HAN ◽

Mihae HONG ◽

Wonhwa CHO

Keyword(s):

Phospholipase A2 ◽

Active Site ◽

Molecular Basis ◽

Mammalian Cells ◽

Inflammatory Cells ◽

Head Group ◽

Human Group ◽

Group V ◽

Head Groups ◽

Hydrolysis Of

Human group-V phospholipase A2 (hVPLA2) is a secretory phospholipase A2 (PLA2) that is involved in eicosanoid formation in such inflammatory cells as macrophages and mast cells. We showed that hVPLA2 can bind phosphatidylcholine membranes and hydrolyse phosphatidylcholine molecules much more efficiently than human group-IIa PLA2, which accounts for its high activity on the outer plasma membrane of mammalian cells. To understand the molecular basis of the high phosphatidylcholine specificity of hVPLA2, we mutated several residues (Gly-53, Glu-56 and Glu-57) that might be involved in interaction with an active-site-bound phospholipid molecule. Phospholipid head-group specificities of mutants determined using polymerized mixed-liposome substrates indicate that a small glycine residue in position 53 is important for accommodating a bulky choline head group. Also, results indicated that two anionic residues, Glu-56 and Glu-57, favourably interact with cationic head groups of phosphatidylcholine and phosphatidylethanolamine. Together, these steric and electrostatic properties of the active site of hVPLA2 allow for effective binding and hydrolysis of a bulky cationic choline head group of phosphatidylcholine, which is unique among mammalian secretory PLA2s.

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Potent and selective 2-oxoamide inhibitors of phospholipases A2 as novel medicinal agents for the treatment of inflammatory diseases

Pure and Applied Chemistry ◽

10.1351/pac-con-11-10-32 ◽

2012 ◽

Vol 84 (9) ◽

pp. 1877-1894 ◽

Cited By ~ 4

Author(s):

Efrosini Barbayianni ◽

Georgia Antonopoulou ◽

George Kokotos

Keyword(s):

Amino Acids ◽

Fatty Acids ◽

Inflammatory Diseases ◽

Ester Bond ◽

Selective Inhibitors ◽

Phospholipases A2 ◽

Hydrolysis Of ◽

Major Target ◽

Phospholipases A

Phospholipases A2 (PLA2s) are enzymes that are capable of catalyzing the hydrolysis of the sn-2 ester bond of glycerophospholipids, releasing free fatty acids, including arachidonic acid (AA), and lysophospholipids. Both products are precursor signaling molecules involved in inflammation. Among the various PLA2s, cytosolic GIVA cPLA2 is considered a major target for inflammatory diseases, while secreted GIIA sPLA2 is involved in cardiovascular diseases. We have developed lipophilic 2-oxoamides based on (S)-γ- or δ-amino acids as potent and selective inhibitors of GIVA cPLA2, which present interesting in vivo anti-inflammatory activity. 2-Oxoamides based on natural α-amino acids are selective inhibitors of GIIA sPLA2. The mode of binding of 2-oxoamides with either GIVA cPLA2 or GIIA sPLA2 has been studied by various techniques.

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Hydrolysis of Phosphatidylcholine-Isoprostanes (PtdCho-IP) by Peripheral Human Group IIA, V and X Secretory Phospholipases A2 (sPLA2)

Lipids ◽

10.1007/s11745-017-4264-z ◽

2017 ◽

Vol 52 (6) ◽

pp. 477-488 ◽

Cited By ~ 2

Author(s):

Arnis Kuksis ◽

Waldemar Pruzanski

Keyword(s):

Human Group ◽

Phospholipases A2 ◽

Hydrolysis Of

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Hydrolysis of UV-induced peroxidized phosphatidylcholine initiated by phospholipases of different substrate specificities

Proceedings of the National Academy of Sciences of Belarus Chemical Series ◽

10.29235/1561-8331-2021-57-2-195-205 ◽

2021 ◽

Vol 57 (2) ◽

pp. 195-205

Author(s):

N. M. Litvinko

Keyword(s):

Uv Irradiation ◽

Sodium Deoxycholate ◽

Lipid Phase ◽

Supramolecular Organization ◽

Uv Spectrum ◽

Pancreatic Phospholipase ◽

Interfacial Surface ◽

A Site ◽

Hydrolysis Of ◽

Phospholipases A

The activity of porcine pancreatic phospholipase A2 and the same of cobra venom toward phosphatidylcholine having different supramolecular organization and interfacial charge (micelles with sodium deoxycholate and liposomes) under UV irradiation (180–400 nm) was studied. It was shown that the UV-irradiated lipid phase is characterized by an increased index of phosphatidylcholine oxidation and the absence of a peak with a maximum of 235.5 nm, related to the presence of unsaturated bonds in the UV spectrum of docosahexaenoic acid, but retained in the presence of the antioxidant trolox. The activation of both phospholipases A2 after UV irradiation of the substrate was established, regardless of its supramolecular organization, the charge of the interfacial surface, and the substrate specificity of the enzymes. Using dynamic light scattering, 0.3 % of larger particles were found among the irradiated micelles of phosphatidylcholine. The results obtained indicate that areas of accumulation of hydroperoxidized lipids can be formed in the irradiated model membrane, which serve as a site of intensified attack for phospholipases.

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Is dipalmitoylphosphatidylcholine a substrate for convertase?

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2000.278.1.l19 ◽

2000 ◽

Vol 278 (1) ◽

pp. L19-L24 ◽

Cited By ~ 2

Author(s):

Rajiv Dhand ◽

Jared Young ◽

Andelle Teng ◽

Subbiah Krishnasamy ◽

Nicholas J. Gross

Keyword(s):

Phospholipase D ◽

Broad Band ◽

Major Phospholipid ◽

Natural Surfactant ◽

Liver Esterase ◽

Hydrolysis Of ◽

Phospholipases A

Convertase has homology with carboxylesterases, but its substrate(s) is not known. Accordingly, we determined whether dipalmitoylphosphatidylcholine (DPPC), the major phospholipid in surfactant, was a substrate for convertase. We measured [3H]choline release during cycling of the heavy subtype containing [3H]choline-labeled DPPC with convertase, phospholipases A2, B, C, and D, liver esterase, and elastase. Cycling with liver esterase or peanut or cabbage phospholipase D produced the characteristic profile of heavy and light peaks observed on cycling with convertase. In contrast, phospholipases A2, B, and C and yeast phospholipase D produced a broad band of radioactivity across the gradient without distinct peaks. [3H]choline was released when natural surfactant containing [3H]choline-labeled DPPC was cycled with yeast phospholipase D but not with convertase or peanut and cabbage phospholipases D. Similarly, yeast phospholipase D hydrolyzed [3H]choline from [3H]choline-labeled DPPC after incubation in vitro, whereas convertase, liver esterase, or peanut and cabbage phospholipases D did not. Thus convertase, liver esterase, and plant phospholipases D did not hydrolyze choline from DPPC either on cycling or during incubation with enzyme in vitro. In conclusion, conversion of heavy to light subtype of surfactant by convertase may require a phospholipase D type hydrolysis of phospholipids, but the substrate in this reaction is not DPPC.

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