Phospholipases A<sub>2</sub>: structure and function

Wilton, David C.

doi:10.1002/ejlt.200401089

Cited by 15 publications

(9 citation statements)

References 113 publications

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“…Activation of the function of cPLA 2 is mediated by Ca 2+ and MAPK (33). In response to Ag stimulation, the intracellular Ca 2+ level increases so Ca 2+ can bind to the C2 domain of cPLA 2.…”

Section: Discussionmentioning

confidence: 99%

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Lee

Kim

et al. 2012

The Journal of Immunology

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Neutrophils are inflammatory cells that may contribute in a crucial way to the pathophysiology of steroid-resistant severe asthma. We previously reported that the nonessential amino acid l-glutamine (Gln) suppressed the recruitment of neutrophils into the airway in a murine model of asthma. In this study, we investigated the mechanisms by which Gln exerts beneficial effects in airway neutrophilia. We used the model we previously developed, which is suitable for examining sequential early asthmatic events, including neutrophil infiltration. Gln suppressed airway neutrophilia in a CXC chemokine-independent way. Airway neutrophilia was associated with cytosolic phospholipase A2 (cPLA2) and 5-lipoxygenase (5-LO) activities. p38 MAPK, the upstream pathway of cPLA2 and 5-LO, played a key role in inducing airway neutrophilia. Gln inhibited not only the phosphorylation of cPLA2 and p38 MAPK but also leukotriene B4 levels in the airways. Gln induced the early induction of MAPK phosphatase-1 (MKP-1) protein, a negative regulator of p38. MKP-1 small interfering RNA abrogated all the effects of Gln. Our results suggest that pathways involving p38/cPLA2/5-LO have a major role in airway neutrophilia. Gln suppresses airway neutrophilia via inhibiting p38 MAPK and its downstream pathways in an MKP-1–dependent way, which may provide a novel therapeutic strategy for pulmonary neutrophilic inflammatory diseases.

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Section: Discussionmentioning

confidence: 99%

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Lee

Kim

et al. 2012

The Journal of Immunology

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“…With the development of biotechnology, a number of phospholipases were expressed in hosts other than the native ones (fungi, microbes, plants). This fact has led to the production of new phospholipases and the development of novel industrial applications [11,21].…”

Section: Introductionmentioning

confidence: 99%

Emulsifying Properties of Different Modified Sunflower Lecithins

Cabezas

Madoery

Diehl³

et al. 2011

J Americ Oil Chem Soc

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Lecithins are a mixture of acetone-insoluble phospholipids and other minor substances (triglycerides, carbohydrates, etc.). The most commonly processes used for lecithin modification are: fractionation by deoiling to separate oil from phospholipids, fractionation with solvents to produce fractions enriched in specific phospholipids, and introduction of enzymatic and chemical changes in phospholipid molecules. The aim of this work was to evaluate the emulsifying properties of different modified sunflower lecithins in oil-in-water (O/W) emulsions. In this study, five modified sunflower lecithins were assessed, which were obtained by deoiling (deoiled lecithin), fractionation with absolute ethanol (PC and PI enriched fractions), and enzymatic hydrolysis with phospholipase A 2 from pancreatic porcine and microbial sources (hydrolyzed lecithins). Modified lecithins were applied as an emulsifying agent in O/W emulsions (30:70 wt/wt), ranging 0.1-2.0% (wt/wt). Stability of different emulsions was evaluated through the evolution of backscattering profiles (%BS), particle size distribution, and mean particle diameters (D [3, 4], D [3, 2]). PC enriched fraction and both hydrolyzed lecithins presented the best emulsifying properties against the main destabilization processes (creaming and coalescence) for the analyzed emulsions. These modified lecithins represent a good alternative for the production of new bioactive agents.

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“…Activation of cPLA 2 is mediated by Ca 2+ and MAPK [31]. Activation of the hydrolyzing function of cPLA 2 requires additional phosphorylation by MAPKs.…”

Section: Discussionmentioning

confidence: 99%

Glutamine Prevents Late-Phase Anaphylaxis via MAPK Phosphatase 1-Dependent Cytosolic Phospholipase A<sub>2</sub> Deactivation

Kim¹,

Song

Bae

et al. 2016

Int Arch Allergy Immunol

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Background: Cytosolic phospholipase A₂ (cPLA₂) plays a key role in the development of late-phase anaphylaxis. L-Glutamine (Gln), a nonessential amino acid, has anti-inflammatory activity via inhibiting cPLA₂. Methods: We used a penicillin-induced murine model of anaphylaxis, and late-phase anaphylaxis was quantified by measuring the increase in the hematocrit (Ht) value. Various inhibitors, small interfering RNA, and knockout mice were used in inhibition experiments. Phosphorylation and protein expression of cPLA₂, ERK, and MAPK phosphatase 1 (MKP-1) were detected by Western blotting. Results: Leukotriene (LT) B₄ was found to be another potent inducer of late-phase anaphylaxis besides the known mediator platelet-activating-factor (PAF). Gln efficiently prevented late-phase anaphylaxis when it was administered up to 3 h after challenge injection via inhibiting cPLA₂. Inhibition studies indicated that p38 MAPK was the major upstream regulator of cPLA₂. Gln dephosphorylated p38 and cPLA₂ via up-regulating the negative regulator of p38 MAPK, i.e., MKP-1 protein. MKP-1 blockade abrogated all the effects of Gln. Conclusion: Of the cPLA₂ metabolites, PAF and LTB₄ play a key role in the development of late-phase anaphylaxis, and Gln prevents the reaction via MKP-1-dependent deactivation of cPLA₂.

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Phospholipases A₂: structure and function

Cited by 15 publications

References 113 publications

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Emulsifying Properties of Different Modified Sunflower Lecithins

Glutamine Prevents Late-Phase Anaphylaxis via MAPK Phosphatase 1-Dependent Cytosolic Phospholipase A<sub>2</sub> Deactivation

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Phospholipases A2: structure and function

Cited by 15 publications

References 113 publications

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Glutamine Suppresses Airway Neutrophilia by Blocking Cytosolic Phospholipase A2 via an Induction of MAPK Phosphatase-1

Emulsifying Properties of Different Modified Sunflower Lecithins

Glutamine Prevents Late-Phase Anaphylaxis via MAPK Phosphatase 1-Dependent Cytosolic Phospholipase A<sub>2</sub> Deactivation

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Phospholipases A₂: structure and function