51
|
Liu Y, Chen LY, Sokolowska M, Eberlein M, Alsaaty S, Martinez-Anton A, Logun C, Qi HY, Shelhamer JH. The fish oil ingredient, docosahexaenoic acid, activates cytosolic phospholipase A₂ via GPR120 receptor to produce prostaglandin E₂ and plays an anti-inflammatory role in macrophages. Immunology 2014; 143:81-95. [PMID: 24673159 DOI: 10.1111/imm.12296] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 03/11/2014] [Accepted: 03/21/2014] [Indexed: 12/13/2022] Open
Abstract
Docosahexaenoic acid (DHA) is one of the major ingredients of fish oil and has been reported to have anti-inflammatory properties mediated through the GPR120 receptor. Whether cytosolic phospholipase A2 (cPLA2 ) and lipid mediators produced from cPLA2 activation are involved in the anti-inflammatory role of DHA in macrophages has not been reported. We report here that DHA and the GPR120 agonist, GW9508, activate cPLA2 and cyclooxygenase 2 (COX-2), and cause prostaglandin E2 (PGE2) release in a murine macrophage cell line RAW264.7 and in human primary monocyte-derived macrophages. DHA and GW9508 activate cPLA2 via GPR120 receptor, G protein Gαq and scaffold protein β-arrestin 2. Extracellular signal-regulated kinase 1/2 activation is involved in DHA- and GW9508-induced cPLA2 activation, but not p38 mitogen-activated protein kinase. The anti-inflammatory role of DHA and GW9508 is in part via activation of cPLA2 , COX-2 and production of PGE2 as a cPLA2 inhibitor or a COX-2 inhibitor partially reverses the DHA- and GW9508-induced inhibition of lipopolysaccharide-induced interleukin-6 secretion. The cPLA2 product arachidonic acid and PGE2 also play an anti-inflammatory role. This effect of PGE2 is partially through inhibition of the nuclear factor-κB signalling pathway and through the EP4 receptor of PGE2 because an EP4 inhibitor or knock-down of EP4 partially reverses DHA inhibition of lipopolysaccharide-induced interleukin-6 secretion. Hence, DHA has an anti-inflammatory effect partially through induction of PGE2.
Collapse
Affiliation(s)
- Yueqin Liu
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
52
|
Guillemot L, Medina M, Pernet E, Leduc D, Chignard M, Touqui L, Wu Y. Cytosolic phospholipase A2α enhances mouse mortality induced by Pseudomonas aeruginosa pulmonary infection via interleukin 6. Biochimie 2014; 107 Pt A:95-104. [PMID: 25201511 DOI: 10.1016/j.biochi.2014.08.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/29/2014] [Indexed: 12/19/2022]
Abstract
Pseudomonas aeruginosa pulmonary infection is a leading cause of death in numerous diseases such as cystic fibrosis (CF). The host cytosolic phospholipase A2α (cPLA2α) releases lipid mediators that play an important role in the pathogenesis of diseases, but its role in lung injury induced by P. aeruginosa infection is still obscure. Using an animal model of P. aeruginosa lung infection, we showed that the CHA strain of P. aeruginosa was more potent than the PAK strain in inducing mouse mortality and lung injury, and that both mouse mortality and lung injury were reduced in cPLA2α(-/-) mice as compared to cPLA2α(+/+) mice. This was accompanied by decreased levels of IL6 but not other inflammatory cytokines (IL1β, KC and TNFα) in the bronchoalveolar lavage fluids (BALFs) of cPLA2α(-/-) mice. Given that CFTR(-/-) mice exhibit increased cPLA2α activation in the lung, the role of cPLA2α was further examined in this lung infection model. Compared to littermates, P. aeruginosa infection caused increased mortality in CFTR(-/-) mice with high IL6 levels in BALFs, which was attenuated by pharmacological inhibition of cPLA2α. In addition, compared to IL6(-/-) mice, an enhanced mortality was also observed in P. aeruginosa infected IL6(+/+) mice. Since alveolar macrophages (AMs) are the primary inflammatory cytokine source in the lung, murine AMs cell line (MH-S) were used to investigate the signalling pathways involved in this process. Incubation of MH-S cells with P. aeruginosa induced IL6 production, which was mediated by MAPKs ERK/p38 and was abolished by cPLA2α inhibitors. Furthermore, among cPLA2 downstream signalling pathways, only 15-lipoxygenase (15-LOX) and cyclooxygenase-2 (COX-2) were proven to participate in this P. aeruginosa-induced IL6 expression. Based on all these observations, we conclude that cPLA2α enhances P. aeruginosa-induced animal lethality in part via IL6 induction and that MAPKs ERK/p38, 15-LOX and COX-2 signalling pathways were involved in this process.
Collapse
Affiliation(s)
- Laurent Guillemot
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Mathieu Medina
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Erwan Pernet
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Dominique Leduc
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Michel Chignard
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Lhousseine Touqui
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France
| | - Yongzheng Wu
- Unit of Innate Defence & Inflammation, Institut Pasteur, 25 rue Dr Roux, 75015 Paris, France; INSERM U874, 25 rue Dr Roux, 75015 Paris, France.
| |
Collapse
|
53
|
Phospholipase A(2) activation by poultry particulate matter is mediated through extracellular signal-regulated kinase in lung epithelial cells: regulation of interleukin-8 release. Cell Biochem Biophys 2014; 67:415-29. [PMID: 22183614 DOI: 10.1007/s12013-011-9329-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
The mechanisms of poultry particulate matter (PM)-induced agricultural respiratory disorders are not thoroughly understood. Hence, it is hypothesized in this article that poultry PM induces the release of interleukin-8 (IL-8) by lung epithelial cells that is regulated upstream by the concerted action of cytosolic phospholipase A2 (cPLA2) and extracellular signal-regulated kinase (ERK). To test this hypothesis, the widely used cultured human lung epithelial cells (A549) were chosen as the model system. Poultry PM caused a significant activation of PLA2 in A549 cells, which was attenuated by AACOCF3 (cPLA2 inhibitor) and PD98059 (ERK-1/2 upstream inhibitor). Poultry PM induced upstream ERK-1/2 phosphorylation and downstream cPLA2 serine phosphorylation, in a concerted fashion, in cells with enhanced association of ERK-1/2 and cPLA2. The poultry PM-induced cPLA2 serine phosphorylation and IL-8 release were attenuated by AACOCF3, PD98059, and by transfection with dominant-negative ERK-1/2 DNA in cells. The poultry PM-induced IL-8 release by the bone marrow-derived macrophages of cPLA2 knockout mice was significantly lower. For the first time, this study demonstrated that the poultry PM-induced IL-8 secretion by human lung epithelial cells was regulated by cPLA2 activation through ERK-mediated serine phosphorylation, suggesting a mechanism of airway inflammation among poultry farm workers.
Collapse
|
54
|
Slone EA, Fleming SD. Membrane lipid interactions in intestinal ischemia/reperfusion-induced Injury. Clin Immunol 2014; 153:228-40. [PMID: 24814240 DOI: 10.1016/j.clim.2014.04.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 04/10/2014] [Accepted: 04/29/2014] [Indexed: 01/02/2023]
Abstract
Ischemia, lack of blood flow, and reperfusion, return of blood flow, are a common phenomenon affecting millions of Americans each year. Roughly 30,000 Americans per year experience intestinal ischemia-reperfusion (IR), which is associated with a high mortality rate. Previous studies of the intestine established a role for neutrophils, eicosanoids, the complement system and naturally occurring antibodies in IR-induced pathology. Furthermore, data indicate involvement of a lipid or lipid-like moiety in mediating IR-induced damage. It has been proposed that antibodies recognize exposure of neo-antigens, triggering action of the complement cascade. While it is evident that the pathophysiology of IR-induced injury is complex and multi-factorial, we focus this review on the involvement of eicosanoids, phospholipids and neo-antigens in the early pathogenesis. Lipid changes occurring in response to IR, neo-antigens exposed and the role of a phospholipid transporter, phospholipid scramblase 1 will be discussed.
Collapse
Affiliation(s)
- Emily Archer Slone
- College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
| | - Sherry D Fleming
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA.
| |
Collapse
|
55
|
Liu NK, Deng LX, Zhang YP, Lu QB, Wang XF, Hu JG, Oakes E, Bonventre JV, Shields CB, Xu XM. Cytosolic phospholipase A2 protein as a novel therapeutic target for spinal cord injury. Ann Neurol 2014; 75:644-58. [PMID: 24623140 PMCID: PMC4320750 DOI: 10.1002/ana.24134] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 02/28/2014] [Accepted: 03/10/2014] [Indexed: 12/17/2022]
Abstract
Objective The objective of this study was to investigate whether cytosolic phospholipase A2 (cPLA2), an important isoform of PLA2 that mediates the release of arachidonic acid, plays a role in the pathogenesis of spinal cord injury (SCI). Methods A combination of molecular, histological, immunohistochemical, and behavioral assessments were used to test whether blocking cPLA2 activation pharmacologically or genetically reduced cell death, protected spinal cord tissue, and improved behavioral recovery after a contusive SCI performed at the 10th thoracic level in adult mice. Results SCI significantly increased cPLA2 expression and activation. Activated cPLA2 was localized mainly in neurons and oligodendrocytes. Notably, the SCI-induced cPLA2 activation was mediated by the extracellular signal-regulated kinase signaling pathway. In vitro, activation of cPLA2 by ceramide-1-phosphate or A23187 induced spinal neuronal death, which was substantially reversed by arachidonyl trifluoromethyl ketone, a cPLA2 inhibitor. Remarkably, blocking cPLA2 pharmacologically at 30 minutes postinjury or genetically deleting cPLA2 in mice ameliorated motor deficits, and reduced cell loss and tissue damage after SCI. Interpretation cPLA2 may play a key role in the pathogenesis of SCI, at least in the C57BL/6 mouse, and as such could be an attractive therapeutic target for ameliorating secondary tissue damage and promoting recovery of function after SCI.
Collapse
Affiliation(s)
- Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, and Goodman Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN
| | | | | | | | | | | | | | | | | | | |
Collapse
|
56
|
Yang P, Jiang Y, Fischer SM. Prostaglandin E3 metabolism and cancer. Cancer Lett 2014; 348:1-11. [PMID: 24657656 DOI: 10.1016/j.canlet.2014.03.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 03/03/2014] [Accepted: 03/07/2014] [Indexed: 01/13/2023]
Abstract
The anticancer activity of n-3 fatty acids, especially those derived from fish, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid) (DHA), has been studied for centuries. While there is a growing body of evidence that EPA and DHA may influence cancer initiation and development through targeting multiple events of tumor development, the underlying mechanisms responsible for these activities are still not fully understood. A number of studies have suggested that the anticancer activities of EPA and DHA are associated with their effects on eicosanoid metabolism by which they inhibit prostaglandin E2 (PGE2) production. In contrast to DHA, EPA can function as a substrate for cyclooxygenases (COXs) to synthesize unique 3-series prostaglandin compounds, especially PGE3. With advance technology in mass spectrometry, there is renewed interest in studying the role of PGE3 in EPA elicited anti-proliferative activity in various cancers, with some promising results. Here, we summarize the regulation of PGE3 synthesis in cancer cells and its role in EPA elicited anticancer activity. The development of PGE3 and its metabolites as potential biomarkers for future clinical evaluation of EPA and fish oil in cancer care is discussed.
Collapse
Affiliation(s)
- Peiying Yang
- Department of General Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States.
| | - Yan Jiang
- Department of General Oncology, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States
| | - Susan M Fischer
- Department of Molecular Carcinogenesis, The University of Texas, MD Anderson Cancer Center, Houston, TX, United States
| |
Collapse
|
57
|
Jin M, Zhou Q, Lee E, Dan S, Duan HQ, Kong D. AS252424, a PI3Kγ Inhibitor, Downregulates Inflammatory Responsiveness in Mouse Bone Marrow-Derived Mast Cells. Inflammation 2014; 37:1254-60. [DOI: 10.1007/s10753-014-9852-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
58
|
Deregulated balance of omega-6 and omega-3 polyunsaturated fatty acids following infection by the zoonotic pathogen Streptococcus suis. Infect Immun 2014; 82:1778-85. [PMID: 24549326 DOI: 10.1128/iai.01524-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for early high mortality in septic shock-like syndrome cases. Polyunsaturated fatty acids (PUFAs) may contribute to regulating inflammatory processes. This study shows that mouse infection by S. suis is accompanied by an increase of arachidonic acid, a proinflammatory omega-6 (ω-6) PUFA, and by a decrease of docosahexaenoic acid, an anti-inflammatory ω-3 PUFA. Macrophages infected with S. suis showed activation of mitogen-activated protein kinase pathways and cyclooxygenase-2 upregulation. Fenretinide, a synthetic vitamin A analog, reduced in vitro expression of inflammatory mediators. Pretreatment of mice with fenretinide significantly improved their survival by reducing systemic proinflammatory cytokines during the acute phase of an S. suis infection. These findings indicate a beneficial effect of fenretinide in diminishing the expression of inflammation and improving survival during an acute infection by a virulent S. suis strain.
Collapse
|
59
|
Melo MCSC, Gadelha D, Mascena GV, Oliveira TKB, Brandt CT. Translational realistic expectations of chronic cerebral hypoxemia in rat model after bilateral commom carotid artery ligation. Neurocognitive aspects. Acta Cir Bras 2014; 29:53-8. [DOI: 10.1590/s0102-86502014000100008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 12/16/2013] [Indexed: 11/21/2022] Open
|
60
|
Heger M, van Golen RF, Broekgaarden M, Michel MC. The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer. Pharmacol Rev 2013; 66:222-307. [PMID: 24368738 DOI: 10.1124/pr.110.004044] [Citation(s) in RCA: 346] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.
Collapse
Affiliation(s)
- Michal Heger
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
| | | | | | | |
Collapse
|
61
|
Choi JM, Choi YH, Kim SK, Ahn KH, Won JH, Lim JH, Jang YJ, Lee S, Kim DH, Kim DK. (S)-tetrahydroisoquinoline alkaloid inhibits LPS-induced arachidonic acid release through downregulation of cPLA2 expression. Mol Cells 2013; 36:400-9. [PMID: 24293010 PMCID: PMC3887938 DOI: 10.1007/s10059-013-0078-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 09/10/2013] [Accepted: 09/15/2013] [Indexed: 01/24/2023] Open
Abstract
Sepsis, a systemic inflammatory response syndrome, remains a potentially lethal condition. (S)-1-α-Naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (CKD712) is noted as a drug candidate for sepsis. Many studies have demonstrated its significant anti-inflammatory effects. Here we first examined whether CKD712 inhibits lipopolysaccharide (LPS)-induced arachidonic acid (AA) release in the RAW 264.7 mouse monocyte cell line, and subsequently, its inhibitory mechanisms. CKD712 reversed LPS-associated morphological changes in the RAW 264.7 cells, and inhibited LPS-induced release of AA in a concentrationdependent manner. The inhibition was apparently due to the diminished expression of a cytosolic form of phospholipase A2 (cPLA2) by CKD712, resulting from reduced NF-κB activation. Furthermore, CKD712 inhibited the activation of ERK1/2 and SAP/JNK, but not of p38 MAPK. CKD712 had no effect on the activity or phosphorylation of cPLA2 and on calcium influx. Our results collectively suggest that CKD712 inhibits LPS-induced AA release through the inhibition of a MAPKs/NF-κB pathway leading to reduced cPLA2 expression in RAW 264.7 cells.
Collapse
Affiliation(s)
- Jong Min Choi
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Young Hwa Choi
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Seok Kyun Kim
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Kyong Hoon Ahn
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Jong Hoon Won
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - Joo Hyuk Lim
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | - You Jin Jang
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| | | | | | - Dae Kyong Kim
- Department of Environmental and Health Chemistry, College of Pharmacy, Chung-Ang University, Seoul 156-756, Korea
| |
Collapse
|
62
|
Di Gennaro A, Haeggström JZ. Targeting leukotriene B4 in inflammation. Expert Opin Ther Targets 2013; 18:79-93. [PMID: 24090264 DOI: 10.1517/14728222.2013.843671] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Leukotriene (LT) B(4) is a powerful proinflammatory lipid mediator and triggers adherence to the endothelium, activates and recruits leukocytes to the site of injury. When formed in excess, LTB(4) plays a pathogenic role and may sustain chronic inflammation in diseases such as asthma, rheumatoid arthritis, and inflammatory bowel disease. Recent investigations have also indicated that LTB(4) is involved in cardiovascular diseases. AREAS COVERED As the 5-lipoxygenase pathway involves several discrete, tightly coupled, enzymes, which convert the substrate, 'step by step', into bioactive products, several different strategies have been used to target LTB(4) as a means to treat inflammation. Here, we discuss recent findings regarding the development of selective enzyme inhibitors and antagonists for LTB(4) receptors, as well as their application in preclinical and clinical studies. EXPERT OPINION Components of the 5-lipoxygenase pathway have received considerable attention as candidate drug targets resulting in one new class of medications against asthma, that is, the antileukotrienes. However, efforts to specifically target LTB(4) have not yet been fruitful in the clinical setting, in spite of very promising preclinical data. Recently, crystal structures along with hitherto unknown functions of key enzymes in the leukotriene cascade have emerged, offering new opportunities for drug development and, with time, pharmacological intervention in LTB(4)-mediated pathologies.
Collapse
Affiliation(s)
- Antonio Di Gennaro
- Karolinska Institutet, Department of Medical Biochemistry and Biophysics, Division of Chemistry 2 , Scheeles väg 2, Stockholm, S-171 77 , Sweden
| | | |
Collapse
|
63
|
Spitler KM, Matsumoto T, Webb RC. Suppression of endoplasmic reticulum stress improves endothelium-dependent contractile responses in aorta of the spontaneously hypertensive rat. Am J Physiol Heart Circ Physiol 2013; 305:H344-53. [PMID: 23709602 DOI: 10.1152/ajpheart.00952.2012] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A contributing factor to increased peripheral resistance seen during hypertension is an increased production of endothelium-derived contractile factors (EDCFs). The main EDCFs are vasoconstrictor prostanoids, metabolites of arachidonic acid (AA) produced by Ca(2+)-dependent cytosolic phospholipase A2 (cPLA2) following phosphorylation (at Ser(505)) mediated by extracellular signal-regulated kinase (ERK1/2) and cyclooxygenase (COX) activations. Although endoplasmic reticulum (ER) stress has been shown to contribute to pathophysiological alterations in cardiovascular diseases, the relationship between ER stress and EDCF-mediated responses remains unclear. We tested the hypothesis that ER stress plays a role in EDCF-mediated responses via activation of the cPLA2/COX pathway in the aorta of the spontaneously hypertensive rat (SHR). Male SHR and Wistar-Kyoto rats (WKY) were treated with ER stress inhibitor, tauroursodeoxycholic acid or 4-phenlybutyric acid (TUDCA or PBA, respectively, 100 mg·kg(-1)·day(-1) ip) or PBS (control, 300 μl/day ip) for 1 wk. There was a decrease in systolic blood pressure in SHR treated with TUDCA or PBA compared with control SHR (176 ± 3 or 181 ± 5, respectively vs. 200 ± 2 mmHg). In the SHR, treatment with TUDCA or PBA normalized aortic (vs. control SHR) 1) contractions to acetylcholine (ACh), AA, and tert-butyl hydroperoxide, 2) ACh-stimulated releases of prostanoids (thromboxane A2, PGF2α, and prostacyclin), 3) expression of COX-1, 4) phosphorylation of cPLA2 and ERK1/2, and 5) production of H2O2. Our findings demonstrate a novel interplay between ER stress and EDCF-mediated responses in the aorta of the SHR. Moreover, ER stress inhibition normalizes such responses by suppressing the cPLA2/COX pathway.
Collapse
Affiliation(s)
- Kathryn M Spitler
- Department of Physiology, Georgia Regents University, Augusta, GA 30912, USA.
| | | | | |
Collapse
|
64
|
Abstract
Diabetes mellitus is responsible for nearly 10% of fetal anomalies in diabetic pregnancies. Although aggressive perinatal care and glycemic control are available in developed countries, the birth defect rate in diabetic pregnancies remains higher than that in the general population. Major cellular activities (ie, proliferation and apoptosis) and intracellular metabolic conditions (ie, nitrosative, oxidative, and endoplasmic reticulum stress) have been shown to be associated with diabetic embryopathy using animal models. Translating advances made in animal studies into clinical applications in humans requires collaborative efforts across the basic research, preclinical, and clinical communities.
Collapse
Affiliation(s)
- Zhiyong Zhao
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | | |
Collapse
|
65
|
Ward KE, Bhardwaj N, Vora M, Chalfant CE, Lu H, Stahelin RV. The molecular basis of ceramide-1-phosphate recognition by C2 domains. J Lipid Res 2013; 54:636-648. [PMID: 23277511 PMCID: PMC3617939 DOI: 10.1194/jlr.m031088] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 12/29/2012] [Indexed: 11/20/2022] Open
Abstract
Group IVA cytosolic phospholipase A₂ (cPLA₂α), which harbors an N-terminal lipid binding C2 domain and a C-terminal lipase domain, produces arachidonic acid from the sn-2 position of zwitterionic lipids such as phosphatidylcholine. The C2 domain has been shown to bind zwitterionic lipids, but more recently, the anionic phosphomonoester sphingolipid metabolite ceramide-1-phosphate (C1P) has emerged as a potent bioactive lipid with high affinity for a cationic patch in the C2 domain β-groove. To systematically analyze the role that C1P plays in promoting the binding of cPLA₂α-C2 to biological membranes, we employed biophysical measurements and cellular translocation studies along with mutagenesis. Biophysical and cellular translocation studies demonstrate that C1P specificity is mediated by Arg⁵⁹, Arg⁶¹, and His⁶² (an RxRH sequence) in the C2 domain. Computational studies using molecular dynamics simulations confirm the origin of C1P specificity, which results in a spatial shift of the C2 domain upon membrane docking to coordinate the small C1P headgroup. Additionally, the hydroxyl group on the sphingosine backbone plays an important role in the interaction with the C2 domain, further demonstrating the selectivity of the C2 domain for C1P over phosphatidic acid. Taken together, this is the first study demonstrating the molecular origin of C1P recognition.
Collapse
Affiliation(s)
- Katherine E. Ward
- Department of Chemistry and Biochemistry and the Mike and Josie Harper Center for Cancer Research, University of Notre Dame, Notre Dame, IN
| | - Nitin Bhardwaj
- Bioinformatics Program, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Mohsin Vora
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, South Bend, IN
| | - Charles E. Chalfant
- Department of Biochemistry, Medical College of Virginia Campus, Virginia Commonwealth University, the Massey Cancer Center, and Research and Development, Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, VA
| | - Hui Lu
- Bioinformatics Program, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Robert V. Stahelin
- Department of Chemistry and Biochemistry and the Mike and Josie Harper Center for Cancer Research, University of Notre Dame, Notre Dame, IN
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, South Bend, IN
| |
Collapse
|
66
|
Di Gennaro A, Haeggström JZ. The leukotrienes: immune-modulating lipid mediators of disease. Adv Immunol 2013; 116:51-92. [PMID: 23063073 DOI: 10.1016/b978-0-12-394300-2.00002-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The leukotrienes are important lipid mediators with immune modulatory and proinflammatory properties. Classical bioactions of leukotrienes include chemotaxis, endothelial adherence, and activation of leukocytes, chemokine production, as well as contraction of smooth muscles in the microcirculation and respiratory tract. When formed in excess, these compounds play a pathogenic role in several acute and chronic inflammatory diseases, such as asthma, rheumatoid arthritis, and inflammatory bowel disease. An increasing number of diseases have been linked to inflammation implicating the leukotrienes as potential mediators. For example, recent investigations using genetic, morphological, and biochemical approaches have pointed to the involvement of leukotrienes in cardiovascular diseases including atherosclerosis, myocardial infarction, stroke, and abdominal aortic aneurysm. Moreover, new insights have changed our previous notion of leukotrienes as mediators of inflammatory reactions to molecules that can fine-tune the innate and adaptive immune response. Here, we review the most recent understanding of the leukotriene cascade with emphasis on recently identified roles in immune reactions and pathophysiology.
Collapse
Affiliation(s)
- Antonio Di Gennaro
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, Stockholm, Sweden
| | | |
Collapse
|
67
|
Szymanski PT, Muley P, Ahmed SA, Khalifa S, Fahmy H. Sarcophine-diol inhibits expression of COX-2, inhibits activity of cPLA2, enhances degradation of PLA2 and PLC(γ)1 and inhibits cell membrane permeability in mouse melanoma B16F10 cells. Mar Drugs 2012; 10:2166-2180. [PMID: 23170076 PMCID: PMC3497015 DOI: 10.3390/md10102166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 07/20/2012] [Accepted: 09/21/2012] [Indexed: 12/28/2022] Open
Abstract
Sarcophine-diol (SD) is a semi-synthetic derivative of sarcophine with a significant chemopreventive effect against non-melanoma skin cancer both in vitro and in vivo. Recently, we have studied the effect of SD on melanoma development using the mouse melanoma B₁₆F₁₀ cell line. In this study, our findings show that SD suppresses cell multiplication and diminishes membrane permeability for ethidium bromide (EB), a model marker used to measure cell permeability for Ca²⁺ ions. SD also decreases protein levels of COX-2, and increases degradation of phospholipases PLA₂ and PLC(γ)1 and diminishes enzymatic activity of the Ca²⁺-dependent cPLA₂. This lower membrane permeability for Ca²⁺-ions, associated with SD, is most likely due to the diminished content of lysophosphosphatidylcholine (lysoPC) within cell membranes caused by the effect of SD on PLA₂. The decrease in diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP₃) due to inhibition of PLC(γ)1, leads to the downregulation of Ca²⁺-dependent processes within the cell and also inhibits the formation of tumors. These findings support our previous data suggesting that SD may have significant potential in the treatment of melanoma.
Collapse
Affiliation(s)
- Pawel T. Szymanski
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
| | - Pratik Muley
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
| | - Safwat A. Ahmed
- Department of Pharmacognosy, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt;
| | | | - Hesham Fahmy
- Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007, USA; (P.T.S.); (P.M.)
| |
Collapse
|
68
|
Richter F, Blomberg R, Khare SD, Kiss G, Kuzin AP, Smith AJT, Gallaher J, Pianowski Z, Helgeson RC, Grjasnow A, Xiao R, Seetharaman J, Su M, Vorobiev S, Lew S, Forouhar F, Kornhaber GJ, Hunt JF, Montelione GT, Tong L, Houk KN, Hilvert D, Baker D. Computational design of catalytic dyads and oxyanion holes for ester hydrolysis. J Am Chem Soc 2012; 134:16197-206. [PMID: 22871159 DOI: 10.1021/ja3037367] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nucleophilic catalysis is a general strategy for accelerating ester and amide hydrolysis. In natural active sites, nucleophilic elements such as catalytic dyads and triads are usually paired with oxyanion holes for substrate activation, but it is difficult to parse out the independent contributions of these elements or to understand how they emerged in the course of evolution. Here we explore the minimal requirements for esterase activity by computationally designing artificial catalysts using catalytic dyads and oxyanion holes. We found much higher success rates using designed oxyanion holes formed by backbone NH groups rather than by side chains or bridging water molecules and obtained four active designs in different scaffolds by combining this motif with a Cys-His dyad. Following active site optimization, the most active of the variants exhibited a catalytic efficiency (k(cat)/K(M)) of 400 M(-1) s(-1) for the cleavage of a p-nitrophenyl ester. Kinetic experiments indicate that the active site cysteines are rapidly acylated as programmed by design, but the subsequent slow hydrolysis of the acyl-enzyme intermediate limits overall catalytic efficiency. Moreover, the Cys-His dyads are not properly formed in crystal structures of the designed enzymes. These results highlight the challenges that computational design must overcome to achieve high levels of activity.
Collapse
Affiliation(s)
- Florian Richter
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
69
|
Ward KE, Ropa JP, Adu-Gyamfi E, Stahelin RV. C2 domain membrane penetration by group IVA cytosolic phospholipase A₂ induces membrane curvature changes. J Lipid Res 2012; 53:2656-66. [PMID: 22991194 DOI: 10.1194/jlr.m030718] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group IVA cytosolic phospholipase A(2) (cPLA(2)α) is an 85 kDa enzyme that regulates the release of arachidonic acid (AA) from the sn-2 position of membrane phospholipids. It is well established that cPLA(2)α binds zwitterionic lipids such as phosphatidylcholine in a Ca(2+)-dependent manner through its N-terminal C2 domain, which regulates its translocation to cellular membranes. In addition to its role in AA synthesis, it has been shown that cPLA(2)α promotes tubulation and vesiculation of the Golgi and regulates trafficking of endosomes. Additionally, the isolated C2 domain of cPLA(2)α is able to reconstitute Fc receptor-mediated phagocytosis, suggesting that C2 domain membrane binding is sufficient for phagosome formation. These reported activities of cPLA(2)α and its C2 domain require changes in membrane structure, but the ability of the C2 domain to promote changes in membrane shape has not been reported. Here we demonstrate that the C2 domain of cPLA(2)α is able to induce membrane curvature changes to lipid vesicles, giant unilamellar vesicles, and membrane sheets. Biophysical assays combined with mutagenesis of C2 domain residues involved in membrane penetration demonstrate that membrane insertion by the C2 domain is required for membrane deformation, suggesting that C2 domain-induced membrane structural changes may be an important step in signaling pathways mediated by cPLA(2)α.
Collapse
Affiliation(s)
- Katherine E Ward
- Department of Chemistry and Biochemistry, University of Notre Dame, South Bend, IN 46556, USA
| | | | | | | |
Collapse
|
70
|
A novel C(28)-hydroxylated lupeolic acid suppresses the biosynthesis of eicosanoids through inhibition of cytosolic phospholipase A2. Biochem Pharmacol 2012; 84:681-91. [DOI: 10.1016/j.bcp.2012.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 11/23/2022]
|
71
|
MAP-kinase regulated cytosolic phospholipase A2 activity is essential for production of infectious hepatitis C virus particles. PLoS Pathog 2012; 8:e1002829. [PMID: 22911431 PMCID: PMC3406102 DOI: 10.1371/journal.ppat.1002829] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 06/14/2012] [Indexed: 12/16/2022] Open
Abstract
Hepatitis C virus (HCV) has infected around 160 million individuals. Current therapies have limited efficacy and are fraught with side effects. To identify cellular HCV dependency factors, possible therapeutic targets, we manipulated signaling cascades with pathway-specific inhibitors. Using this approach we identified the MAPK/ERK regulated, cytosolic, calcium-dependent, group IVA phospholipase A2 (PLA2G4A) as a novel HCV dependency factor. Inhibition of PLA2G4A activity reduced core protein abundance at lipid droplets, core envelopment and secretion of particles. Moreover, released particles displayed aberrant protein composition and were 100-fold less infectious. Exogenous addition of arachidonic acid, the cleavage product of PLA2G4A-catalyzed lipolysis, but not other related poly-unsaturated fatty acids restored infectivity. Strikingly, production of infectious Dengue virus, a relative of HCV, was also dependent on PLA2G4A. These results highlight previously unrecognized parallels in the assembly pathways of these human pathogens, and define PLA2G4A-dependent lipolysis as crucial prerequisite for production of highly infectious viral progeny. The human genome encodes more than 30 phospholipase A2s. These enzymes cleave fatty acids at the C2 atom of phosphoglycerides and thus modulate membrane properties. Among all PLA2s only PLA2G4A, which is recruited to perinuclear membranes by Ca2+ and activated by extracellular stimuli via the mitogen activated protein kinase pathway, specifically cleaves lipids with arachidonic acid. Metabolism of arachidonic acid yields prostaglandins and leukotriens, important lipid mediators of inflammation. We show that inhibition of PLA2G4A produces aberrant HCV particles and that infectivity is rescued by addition of arachidonic acid. Our results suggest that a specific lipid (arachidonic acid) is essential for production of highly infectious HCV progeny, likely by creating a membrane environment conducive for efficient incorporation of crucial host and viral factors into the lipid envelope of nascent particles. Strikingly, PLA2G4A is also essential for production of highly infectious Dengue Virus (DENV) particles but not for vesicular stomatitis virus (VSV). These observations argue that HCV and DENV which unlike VSV produce particles at intracellular membranes usurp a common host factor (PLA2G4A) for assembly of highly infectious progeny. These findings open new perspectives for antiviral intervention and highlight thus far unrecognized parallels in the assembly pathway of HCV and DENV.
Collapse
|
72
|
LEHR MATTHIAS. Inhibitors of Cytosolic Phospholipase A2 α as Anti-inflammatory Drugs. ANTI-INFLAMMATORY DRUG DISCOVERY 2012. [DOI: 10.1039/9781849735346-00035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Arachidonic acid derivatives, like prostaglandins and leukotrienes, as well as the alkyl-ether phospholipid platelet-activating factor (PAF) are highly active substances with diverse biological actions. Elevated levels of these lipid mediators in response to a variety of stimuli have been implicated in the pathology of many inflammatory diseases. The rate-limiting step in the generation of prostaglandins, leukotrienes and PAF, respectively, is the cleavage of the sn-2-ester of membrane phospholipids by a phospholipase A2 (PLA2). Among the superfamily of PLA2 enzymes, cytosolic PLA2α (cPLA2α, also referred to as group IVA PLA2) is thought to play the primary role in this biochemical reaction. Therefore, inhibition of cPLA2α activity is an attractive approach to the control of inflammatory disorders.
In this chapter the main groups of cPLA2α inhibitors are described and the problems associated with the development of clinical active drug candidates are discussed. Furthermore, in-vivo data obtained with such compounds in pre-clinical animal models of inflammation will be presented.
Collapse
Affiliation(s)
- MATTHIAS LEHR
- Institute of Pharmaceutical and Medicinal Chemistry University of Münster Hittorfstrasse 58–62, 48149 Münster Germany
| |
Collapse
|
73
|
Bhattacharjee AK, White L, Chang L, Ma K, Harry GJ, Deutsch J, Rapoport SI. Bilateral common carotid artery ligation transiently changes brain lipid metabolism in rats. Neurochem Res 2012; 37:1490-8. [PMID: 22422289 PMCID: PMC3478069 DOI: 10.1007/s11064-012-0740-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 01/04/2012] [Accepted: 02/20/2012] [Indexed: 10/28/2022]
Abstract
Brain lipid metabolism was studied in rats following permanent bilateral common carotid artery ligation (BCCL), a model for chronic cerebral hypoperfusion. Unesterified (free) fatty acids (uFA) and acyl-CoA concentrations were measured 6 h, 24 h, and 7 days after BCCL or sham surgery, in high energy-microwaved brain. In BCCL compared to sham rats, cytosolic phospholipase A(2) (cPLA(2)) immunoreactivity in piriform cortex, and concentrations of total uFA and arachidonoyl-CoA, an intermediate for arachidonic acid reincorporation into phospholipids, were increased only at 6 h. At 24 h, immunoreactivity for secretory phospholipase A(2) (sPLA(2)), which may regulate blood flow, was increased near cortical and hippocampal blood vessels. BCCL did not affect levels of brain IB(4)+ microglia, glial fibrillary acidic protein (GFAP)+ astrocytes, cyclooxygenase-2 (COX-2) immunoreactivity at any time, but increased cPLA(2) immunoreactivity in one region at 6 h. Thus, BCCL affected brain lipid metabolism transiently, likely because of compensatory sPLA(2)-mediated vasodilation, without producing evidence of neuroinflammation.
Collapse
Affiliation(s)
- Abesh Kumar Bhattacharjee
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Laura White
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Lisa Chang
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Kaizong Ma
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - G. Jean Harry
- Neurotoxicology Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Joseph Deutsch
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
- The Hebrew University of Jerusalem, School of Pharmacy, Jerusalem, Israel
| | - Stanley I. Rapoport
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
74
|
Basselin M, Ramadan E, Rapoport SI. Imaging brain signal transduction and metabolism via arachidonic and docosahexaenoic acid in animals and humans. Brain Res Bull 2012; 87:154-71. [PMID: 22178644 PMCID: PMC3274571 DOI: 10.1016/j.brainresbull.2011.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/01/2011] [Accepted: 12/02/2011] [Indexed: 02/05/2023]
Abstract
The polyunsaturated fatty acids (PUFAs), arachidonic acid (AA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), important second messengers in brain, are released from membrane phospholipid following receptor-mediated activation of specific phospholipase A(2) (PLA(2)) enzymes. We developed an in vivo method in rodents using quantitative autoradiography to image PUFA incorporation into brain from plasma, and showed that their incorporation rates equal their rates of metabolic consumption by brain. Thus, quantitative imaging of unesterified plasma AA or DHA incorporation into brain can be used as a biomarker of brain PUFA metabolism and neurotransmission. We have employed our method to image and quantify effects of mood stabilizers on brain AA/DHA incorporation during neurotransmission by muscarinic M(1,3,5), serotonergic 5-HT(2A/2C), dopaminergic D(2)-like (D(2), D(3), D(4)) or glutamatergic N-methyl-d-aspartic acid (NMDA) receptors, and effects of inhibition of acetylcholinesterase, of selective serotonin and dopamine reuptake transporter inhibitors, of neuroinflammation (HIV-1 and lipopolysaccharide) and excitotoxicity, and in genetically modified rodents. The method has been extended for the use with positron emission tomography (PET), and can be employed to determine how human brain AA/DHA signaling and consumption are influenced by diet, aging, disease and genetics.
Collapse
Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Stanley I. Rapoport
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| |
Collapse
|
75
|
Desbène C, Malaplate-Armand C, Youssef I, Garcia P, Stenger C, Sauvée M, Fischer N, Rimet D, Koziel V, Escanyé MC, Oster T, Kriem B, Yen FT, Pillot T, Olivier JL. Critical role of cPLA2 in Aβ oligomer-induced neurodegeneration and memory deficit. Neurobiol Aging 2011; 33:1123.e17-29. [PMID: 22188721 DOI: 10.1016/j.neurobiolaging.2011.11.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 12/23/2022]
Abstract
Soluble beta-amyloid (Aβ) oligomers are considered to putatively play a critical role in the early synapse loss and cognitive impairment observed in Alzheimer's disease. We previously demonstrated that Aβ oligomers activate cytosolic phospholipase A(2) (cPLA(2)), which specifically releases arachidonic acid from membrane phospholipids. We here observed that cPLA(2) gene inactivation prevented the alterations of cognitive abilities and the reduction of hippocampal synaptic markers levels noticed upon a single intracerebroventricular injection of Aβ oligomers in wild type mice. We further demonstrated that the Aβ oligomer-induced sphingomyelinase activation was suppressed and that phosphorylation of Akt/protein kinase B (PKB) was preserved in neuronal cells isolated from cPLA(2)(-/-) mice. Interestingly, expression of the Aβ precursor protein (APP) was reduced in hippocampus homogenates and neuronal cells from cPLA(2)(-/-) mice, but the relationship with the resistance of these mice to the Aβ oligomer toxicity requires further investigation. These results therefore show that cPLA(2) plays a key role in the Aβ oligomer-associated neurodegeneration, and as such represents a potential therapeutic target for the treatment of Alzheimer's disease.
Collapse
Affiliation(s)
- Cédric Desbène
- Lipidomix (EA 4422), INPL-ENSAIA, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
76
|
Ramadan E, Basselin M, Taha AY, Cheon Y, Chang L, Chen M, Rapoport SI. Chronic valproate treatment blocks D2-like receptor-mediated brain signaling via arachidonic acid in rats. Neuropharmacology 2011; 61:1256-64. [PMID: 21839100 PMCID: PMC3190603 DOI: 10.1016/j.neuropharm.2011.07.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/12/2011] [Accepted: 07/17/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVE Hyperdopaminergic signaling and an upregulated brain arachidonic acid (AA) cascade may contribute to bipolar disorder (BD). Lithium and carbamazepine, FDA-approved for the treatment of BD, attenuate brain dopaminergic D(2)-like (D(2), D(3), and D(4)) receptor signaling involving AA when given chronically to awake rats. We hypothesized that valproate (VPA), with mood-stabilizing properties, would also reduce D(2)-like-mediated signaling via AA. METHODS An acute dose of quinpirole (1 mg/kg) or saline was administered to unanesthetized rats that had been treated for 30 days with a therapeutically relevant dose of VPA (200 mg/kg/day) or vehicle. Regional brain AA incorporation coefficients, k*, and incorporation rates, J(in), markers of AA signaling and metabolism, were measured by quantitative autoradiography after intravenous [1-(14)C]AA infusion. Whole brain concentrations of prostaglandin (PG)E(2) and thromboxane (TX)B(2) also were measured. RESULTS Quinpirole compared to saline significantly increased k* in 40 of 83 brain regions, and increased brain concentrations of PGE(2) in chronic vehicle-treated rats. VPA treatment by itself reduced concentrations of plasma unesterified AA and whole brain PGE(2) and TXB(2), and blocked the quinpirole-induced increments in k* and PGE(2). CONCLUSION These results further provide evidence that mood stabilizers downregulate brain dopaminergic D(2)-like receptor signaling involving AA.
Collapse
Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | | | | | | | |
Collapse
|
77
|
Ishihara K, Kuroda A, Sugihara K, Kanai S, Nabe T, Akiba S. Regulation of macrophage differentiation and polarization by group IVC phospholipase A2. Biochem Biophys Res Commun 2011; 416:325-30. [DOI: 10.1016/j.bbrc.2011.11.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/05/2011] [Indexed: 01/19/2023]
|
78
|
Haeggström JZ, Funk CD. Lipoxygenase and leukotriene pathways: biochemistry, biology, and roles in disease. Chem Rev 2011; 111:5866-98. [PMID: 21936577 DOI: 10.1021/cr200246d] [Citation(s) in RCA: 591] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jesper Z Haeggström
- Department of Medical Biochemistry and Biophysics, Division of Chemistry 2, Karolinska Institutet, S-171 77 Stockholm, Sweden.
| | | |
Collapse
|
79
|
Leukotriene synthesis inhibitor decreases vasopressin release in the early phase of sepsis. J Neuroimmunol 2011; 238:52-7. [DOI: 10.1016/j.jneuroim.2011.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/25/2011] [Accepted: 08/01/2011] [Indexed: 11/21/2022]
|
80
|
Li X, Weng H, Reece EA, Yang P. SOD1 overexpression in vivo blocks hyperglycemia-induced specific PKC isoforms: substrate activation and consequent lipid peroxidation in diabetic embryopathy. Am J Obstet Gynecol 2011; 205:84.e1-6. [PMID: 21529760 DOI: 10.1016/j.ajog.2011.02.071] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 02/23/2011] [Accepted: 02/28/2011] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Oxidative stress plays a causative role in diabetic embryopathy. We tested whether mitigating oxidative stress, using superoxide dismutase 1 (SOD1) transgenic (Tg) mice, would block hyperglycemia-induced specific protein kinase C (PKC) isoform activation and its downstream cascade. STUDY DESIGN Day 8.5 embryos from nondiabetic wild-type control (NC), diabetic mellitus wild-type (DM), and diabetic SOD1-Tg mice (DM-SOD1-Tg) were used for detection of phosphorylated (p-) PKCα/βII and p-PKCδ, and levels of 2 prominent PKC substrates, phosphorylated myristoylated alanine-rich protein kinase C substrate (MARCKS) and receptor for activated C kinase 1 (RACK1), and lipid peroxidation markers, 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). RESULTS Levels of p-PKCα/βII, p-PKCδ, p-MARCKS, 4-HNE, and MDA were significantly elevated in the DM group compared with those in the NC group and the DM-SOD1-Tg group. The NC and DM-SOD1-Tg groups had comparable levels of these protein and lipid peroxidation markers. RACK1 levels did not differ among the 3 groups. CONCLUSION Mitigating oxidative stress by SOD1 overexpression blocks maternal hyperglycemia-induced activation of specific PKC isoforms and downstream cascades.
Collapse
|
81
|
Affiliation(s)
- Motonao Nakamura
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Hongo, Tokyo, Japan.
| | | |
Collapse
|
82
|
Leistad L, Feuerherm AJ, Faxvaag A, Johansen B. Multiple phospholipase A2 enzymes participate in the inflammatory process in osteoarthritic cartilage. Scand J Rheumatol 2011; 40:308-16. [PMID: 21417548 DOI: 10.3109/03009742.2010.547872] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The aim of this study was to determine the involvement of pro-inflammatory phospholipase A2 (PLA2) enzymes in human chondrocytes from patients with osteoarthritis (OA). METHODS PLA2 involvement in OA chondrocytes was analysed by (a) arachidonic acid (AA) and oleic acid release, (b) PLA2 mRNA analysis, and (c) prostaglandin E2 (PGE2) production in cultured OA chondrocytes in response to various cytokines and platelet activating factor (PAF). RESULTS Pro-inflammatory cytokines and PAF stimulation led to increased AA release, interleukin (IL)-1β and tumour necrosis factor (TNF) being the strongest inducers. The pattern of oleic acid release was similar to but less prominent than AA release, suggesting that predominantly arachidonyl selective enzymes were activated. IL-1β, TNF, IL-6, and IL-8 upregulated secretory group IIA, IID, and V phospholipase A2 (sPLA2-IIA, -IID, -V) and cytosolic group IVA phospholipase A2 (cPLA2-IVA) expression, where induction of chondrocyte sPLA2-IID is a novel finding. Furthermore, IL-1β, TNF, and IL-6 also induced COX2 expression. PAF induced expression of group IIA, IID and IVA PLA2, and COX2. In line with its anti-inflammatory properties, IL-4 was unable to induce either AA release or expression of PLA2s or COX2. IL-1β and TNF strongly increased PGE2 production, with IL-1β as the most prominent inducer. CONCLUSION Multiple PLA2 isoforms are expressed and influenced by pro-inflammatory stimuli in OA chondrocytes. Hence, several PLA2 enzymes may contribute to chondrocyte function by their upregulation and activation, and increased AA release and PGE2 production may therefore be important effectors in OA pathophysiology. PLA2 enzymes and cPLA2-IVA in particular are thus possible therapeutic targets in OA.
Collapse
Affiliation(s)
- L Leistad
- SINTEF Technology and Society, Department of Health, Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | | |
Collapse
|
83
|
Mete A, Andrews G, Bernstein M, Connolly S, Hartopp P, Jackson CG, Lewis R, Martin I, Murray D, Riley R, Robinson DH, Smith GM, Wells E, Withnall WJ. Design of novel and potent cPLA2α inhibitors containing an α-methyl-2-ketothiazole as a metabolically stable serine trap. Bioorg Med Chem Lett 2011; 21:3128-33. [PMID: 21450464 DOI: 10.1016/j.bmcl.2011.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/01/2011] [Accepted: 03/02/2011] [Indexed: 11/29/2022]
Abstract
We report the design of novel, potent cPLA(2)α inhibitors that possess an α-methyl-2-ketothiazole that acts as a serine-reactive moiety. We describe the optimization of the series for potency and metabolic stability towards ketone reduction. This was achieved by attenuating the reactivity of the ketone using a combination of electronic and steric effects.
Collapse
Affiliation(s)
- Antonio Mete
- Department of Medicinal Chemistry, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire LE11 5RH, United Kingdom.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
84
|
Reed KA, Tucker DE, Aloulou A, Adler D, Ghomashchi F, Gelb MH, Leslie CC, Oates JA, Boutaud O. Functional characterization of mutations in inherited human cPLA₂ deficiency. Biochemistry 2011; 50:1731-8. [PMID: 21247147 DOI: 10.1021/bi101877n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Group IVA cytosolic phospholipase A(2) (cPLA(2)α) catalyzes the first step in the arachidonic acid cascade leading to the synthesis of important lipid mediators, the prostaglandins and leukotrienes. We previously described a patient deficient in cPLA(2)α activity, which was associated with mutations in both alleles encoding the enzyme. In this paper, we describe the biochemical characterization of each of these mutations. Using saturating concentrations of calcium, we showed that the R485H mutant was nearly devoid of any catalytic activity, that the S111P mutation did not affect the enzyme activity, and that the known K651R polymorphism was associated with activity slightly higher than that of the wild type. Using MDCK cells, we showed that translocation to the Golgi in response to serum activation was impaired for the S111P mutant but not for the other mutants. Using immortalized mouse lung fibroblasts lacking endogenous cPLA(2)α activity, we showed that both mutations S111P and R485H/K651R caused a profound defect in the enzyme catalytic activity in response to cell stimulation with serum. Taken together, our results show that the S111P mutation hampers calcium binding and membrane translocation without affecting the catalytic activity, and that the mutation R485H does not affect membrane translocation but blocks catalytic activity that leads to inactivation of the enzyme. Interestingly, our results show that the common K651R polymorphism confers slightly higher activity to the enzyme, suggesting a role of this residue in favoring a catalytically active conformation of cPLA(2)α. Our results define how the mutations negatively influence cPLA(2)α function and explain the inability of the proband to release arachidonic acid for eicosanoid production.
Collapse
Affiliation(s)
- Kathleen A Reed
- Department of Medicine, Vanderbilt University, School of Medicine, Nashville, Tennessee 37232-6602, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
85
|
Kandasamy P, Zarini S, Chan ED, Leslie CC, Murphy RC, Voelker DR. Pulmonary surfactant phosphatidylglycerol inhibits Mycoplasma pneumoniae-stimulated eicosanoid production from human and mouse macrophages. J Biol Chem 2011; 286:7841-7853. [PMID: 21205826 DOI: 10.1074/jbc.m110.170241] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mycoplasma pneumoniae is a human pathogen causing respiratory infections that are also associated with serious exacerbations of chronic lung diseases. Membranes and lipoproteins from M. pneumoniae induced a 4-fold increase in arachidonic acid (AA) release from RAW264.7 and a 2-fold increase in AA release from primary human alveolar macrophages. The bacterial lipoprotein mimic and TLR2/1 agonist Pam3Cys and the TLR2/6 agonist MALP-2 produced effects similar to those elicited by M. pneumoniae in macrophages by inducing the phosphorylation of p38(MAPK) and p44/42(ERK1/2) MAP kinases and cyclooxygenase-2 (COX-2) expression. M. pneumoniae induced the generation of prostaglandins PGD(2) and PGE(2) from RAW264.7 cells and thromboxane B(2) (TXB(2)) from human alveolar macrophages. Anti-TLR2 antibody completely abolished M. pneumoniae-induced AA release and TNFα secretion from RAW264.7 cells and human alveolar macrophages. Disruption of the phosphorylation of p44/42(ERK1/2) or inactivation of cytosolic phospholipase A(2)α (cPLA(2)α) completely inhibited M. pneumoniae-induced AA release from macrophages. The minor pulmonary surfactant phospholipid, palmitoyl-oleoyl-phosphatidylglycerol (POPG), antagonized the proinflammatory actions of M. pneumoniae, Pam3Cys, and MALP-2 by reducing the production of AA metabolites from macrophages. The effect of POPG was specific, insofar as saturated PG, and saturated and unsaturated phosphatidylcholines did not have significant effect on M. pneumoniae-induced AA release. Collectively, these data demonstrate that M. pneumoniae stimulates the production of eicosanoids from macrophages through TLR2, and POPG suppresses this pathogen-induced response.
Collapse
Affiliation(s)
| | - Simona Zarini
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011
| | | | - Christina C Leslie
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011; Pediatrics, National Jewish Health, Denver, Colorado, 80206 and
| | - Robert C Murphy
- the Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, Colorado 80011
| | | |
Collapse
|
86
|
|
87
|
Shimshoni JA, Basselin M, Li LO, Coleman RA, Rapoport SI, Modi HR. Valproate uncompetitively inhibits arachidonic acid acylation by rat acyl-CoA synthetase 4: relevance to valproate's efficacy against bipolar disorder. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1811:163-9. [PMID: 21184843 DOI: 10.1016/j.bbalip.2010.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 12/10/2010] [Accepted: 12/15/2010] [Indexed: 01/04/2023]
Abstract
BACKGROUND The ability of chronic valproate (VPA) to reduce arachidonic acid (AA) turnover in brain phospholipids of unanesthetized rats has been ascribed to its inhibition of acyl-CoA synthetase (Acsl)-mediated activation of AA to AA-CoA. Our aim was to identify a rat Acsl isoenzyme that could be inhibited by VPA in vitro. METHODS Rat Acsl3-, Acsl6v1- and Acsl6v2-, and Acsl4-flag proteins were expressed in E. coli, and the ability of VPA to inhibit their activation of long-chain fatty acids to acyl-CoA was estimated using Michaelis-Menten kinetics. RESULTS VPA uncompetitively inhibited Acsl4-mediated conversion of AA and of docosahexaenoic (DHA) but not of palmitic acid to acyl-CoA, but did not affect AA conversion by Acsl3, Acsl6v1 or Acsl6v2. Acsl4-mediated conversion of AA to AA-CoA showed substrate inhibition and had a 10-times higher catalytic efficiency than did conversion of DHA to DHA-CoA. Butyrate, octanoate, or lithium did not inhibit AA activation by Acsl4. CONCLUSIONS VPA's ability to inhibit Acsl4 activation of AA and of DHA to their respective acyl-CoAs, when related to the higher catalytic efficiency of AA than DHA conversion, may account for VPA's selective reduction of AA turnover in rat brain phospholipids, and contribute to VPA's efficacy against bipolar disorder.
Collapse
Affiliation(s)
- Jakob A Shimshoni
- National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | |
Collapse
|
88
|
Yano T, Fujioka D, Saito Y, Kobayashi T, Nakamura T, Obata JE, Kawabata K, Watanabe K, Watanabe Y, Mishina H, Tamaru S, Kugiyama K. Group V secretory phospholipase A2 plays a pathogenic role in myocardial ischaemia-reperfusion injury. Cardiovasc Res 2010; 90:335-43. [PMID: 21169294 DOI: 10.1093/cvr/cvq399] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIMS Group V secretory phospholipase A(2) (sPLA(2)-V) is highly expressed in the heart. This study examined (i) the role of sPLA(2)-V in myocardial ischaemia-reperfusion (I/R) injury and (ii) the cooperative action of sPLA(2)-V and cytosolic PLA(2) (cPLA(2)) in myocardial I/R injury, using sPLA(2)-V knockout (sPLA(2)V(-/-)) mice. METHODS AND RESULTS Myocardial I/R injury was created by 1 h ligation of the left anterior descending coronary artery, followed by 24 h of reperfusion. The sPLA(2)V(-/-) mice had a 44% decrease in myocardial infarct size, a preservation of echocardiographic LV function (%fractional shortening: 40 ± 3.5 vs. 21 ± 4.6, respectively), and lower content of leucotriene B(4) (LTB(4)) and thromboxane B(2) (TXB(2)) (40 and 37% lower, respectively) in the ischaemic myocardium after I/R compared with wild-type (WT) mice. Intraperitoneal administration of AACOCF3 or MAFP, inhibitors of cPLA(2) activity, decreased myocardial infarct size and myocardial content of LTB(4) and TXB(2) in both genotyped mice. The decrease in myocardial infarct size and content of LTB(4) and TXB(2) after cPLA(2) inhibitor administration was greater in WT mice than in sPLA(2)V(-/-) mice. I/R increased phosphorylation of extracellular signal-related kinase 1/2, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases in the ischaemic myocardium in association with cPLA(2) phosphorylation. The I/R-induced increase in the phosphorylation of p38 and cPLA(2) was less in sPLA(2)-V(-/-) mice than in WT mice. Pretreatment with the p38 inhibitor SB202190 suppressed an increase in cPLA(2) phosphorylation after I/R in WT mice. CONCLUSION sPLA(2)-V plays an important role in the pathogenesis of myocardial I/R injury partly in concert with the activation of cPLA(2).
Collapse
Affiliation(s)
- Toshiaki Yano
- Department of Internal Medicine II, Faculty of Medicine, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokato, Yamanashi, Chuo 409-3898, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
89
|
Holinstat M, Boutaud O, Apopa PL, Vesci J, Bala M, Oates JA, Hamm HE. Protease-activated receptor signaling in platelets activates cytosolic phospholipase A2α differently for cyclooxygenase-1 and 12-lipoxygenase catalysis. Arterioscler Thromb Vasc Biol 2010; 31:435-42. [PMID: 21127289 DOI: 10.1161/atvbaha.110.219527] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE The rate-limiting step in the biosynthesis of thromboxane A(2) (TxA(2)) and 12-hydroxyeicosatetraenoic acid (12-HETE) by platelets is activation of cytosolic phospholipase A(2α) (cPLA(2α)), which releases arachidonic acid, which is the substrate for cyclooxygenase-1 (COX-1) and 12-lipoxygenase. We evaluated signaling via the human platelet thrombin receptors, protease-activated receptor (PAR) 1 and PAR4, to the activation of cPLA(2α), which provides a substrate for the biosynthesis of TxA(2) and 12-HETE. METHODS AND RESULTS Stimulating washed human platelets resulted in delayed biosynthesis of 12-HETE, which continues after maximal formation of TxA(2) is completed, suggesting that 12-HETE is not formed by the same pool of arachidonic acid that provides a substrate to COX-1. PAR1-induced formation of TxA(2) was inhibited by the phosphatidylinositol kinase inhibitor LY294002, whereas this inhibitor did not block 12-HETE biosynthesis. Both 1-butanol and propranolol also blocked TxA(2) biosynthesis but did not inhibit 12-HETE formation. CONCLUSIONS The concerted evidence indicates that the platelet thrombin receptors signal activation of cPLA(2α) coupled to COX-1 by a pathway different from that signaling activation of the cPLA(2α) coupled to 12-lipoxygenase.
Collapse
Affiliation(s)
- Michael Holinstat
- Cardeza Foundation for Hematologic Research, Department of Medicine, Thomas Jefferson University, 1015 Walnut Street, Philadelphia, PA 19107, USA.
| | | | | | | | | | | | | |
Collapse
|
90
|
Gabryel B, Bielecka A, Stolecka A, Bernacki J, Langfort J. Cytosolic phospholipase A2 inhibition is involved in the protective effect of nortriptyline in primary astrocyte cultures exposed to combined oxygen-glucose deprivation. Pharmacol Rep 2010; 62:814-26. [DOI: 10.1016/s1734-1140(10)70342-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 03/09/2010] [Indexed: 01/19/2023]
|
91
|
Tosato G, Segarra M, Salvucci O. Cytosolic Phospholipase A2 and Cancer: A Role in Tumor Angiogenesis. J Natl Cancer Inst 2010; 102:1377-9. [DOI: 10.1093/jnci/djq324] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
|
92
|
Basselin M, Rosa AO, Ramadan E, Cheon Y, Chang L, Chen M, Greenstein D, Wohltmann M, Turk J, Rapoport SI. Imaging decreased brain docosahexaenoic acid metabolism and signaling in iPLA(2)β (VIA)-deficient mice. J Lipid Res 2010; 51:3166-73. [PMID: 20686114 DOI: 10.1194/jlr.m008334] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ca(2+)-independent phospholipase A(2)β (iPLA(2)β) selectively hydrolyzes docosahexaenoic acid (DHA, 22:6n-3) in vitro from phospholipid. Mutations in the PLA2G6 gene encoding this enzyme occur in patients with idiopathic neurodegeneration plus brain iron accumulation and dystonia-parkinsonism without iron accumulation, whereas mice lacking PLA2G6 show neurological dysfunction and neuropathology after 13 months. We hypothesized that brain DHA metabolism and signaling would be reduced in 4-month-old iPLA(2)β-deficient mice without overt neuropathology. Saline or the cholinergic muscarinic M(1,3,5) receptor agonist arecoline (30 mg/kg) was administered to unanesthetized iPLA(2)β(-/-), iPLA(2)β(+/-), and iPLA(2)β(+/+) mice, and [1-(14)C]DHA was infused intravenously. DHA incorporation coefficients k* and rates J(in), representing DHA metabolism, were determined using quantitative autoradiography in 81 brain regions. iPLA(2)β(-/-) or iPLA(2)β(+/-) compared with iPLA(2)β(+/+) mice showed widespread and significant baseline reductions in k* and J(in) for DHA. Arecoline increased both parameters in brain regions of iPLA(2)β(+/+) mice but quantitatively less so in iPLA(2)β(-/-) and iPLA(2)β(+/-) mice. Consistent with iPLA(2)β's reported ability to selectively hydrolyze DHA from phospholipid in vitro, iPLA(2)β deficiency reduces brain DHA metabolism and signaling in vivo at baseline and following M(1,3,5) receptor activation. Positron emission tomography might be used to image disturbed brain DHA metabolism in patients with PLA2G6 mutations.
Collapse
Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
93
|
Liu NK, Xu XM. Phospholipase A2 and its molecular mechanism after spinal cord injury. Mol Neurobiol 2010; 41:197-205. [PMID: 20127525 PMCID: PMC9169014 DOI: 10.1007/s12035-010-8101-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 01/08/2010] [Indexed: 12/11/2022]
Abstract
Phospholipases A(2) (PLA(2)s) are a diverse family of lipolytic enzymes which hydrolyze the acyl bond at the sn-2 position of glycerophospholipids to produce free fatty acids and lysophospholipids. These products are precursors of bioactive eicosanoids and platelet-activating factor which have been implicated in pathological states of numerous acute and chronic neurological disorders. To date, more than 27 isoforms of PLA(2) have been found in the mammalian system which can be classified into four major categories: secretory PLA(2), cytosolic PLA(2), Ca(2+)-independent PLA(2), and platelet-activating factor acetylhydrolases. Multiple isoforms of PLA(2) are found in the mammalian spinal cord. Under physiological conditions, PLA(2)s are involved in diverse cellular responses, including phospholipid digestion and metabolism, host defense, and signal transduction. However, under pathological situations, increased PLA(2) activity, excessive production of free fatty acids and their metabolites may lead to the loss of membrane integrity, inflammation, oxidative stress, and subsequent neuronal injury. There is emerging evidence that PLA(2) plays a key role in the secondary injury process after traumatic spinal cord injury. This review outlines the current knowledge of the PLA(2) in the spinal cord with an emphasis being placed on the possible roles of PLA(2) in mediating the secondary SCI.
Collapse
Affiliation(s)
- Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, 950 W. Walnut St., R-2 Building, Room 402, Indianapolis, IN 46202, USA
| | | |
Collapse
|
94
|
Starner RJ, McClelland L, Abdel-Malek Z, Fricke A, Scott G. PGE(2) is a UVR-inducible autocrine factor for human melanocytes that stimulates tyrosinase activation. Exp Dermatol 2010; 19:682-4. [PMID: 20500768 DOI: 10.1111/j.1600-0625.2010.01074.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Prostaglandins activate signalling pathways involved in growth, differentiation and apoptosis. Prostaglandin E(2) (PGE(2)) is released by keratinocytes following ultraviolet irradiation (UVR) and stimulates the formation of dendrites in melanocytes. We show that multiple irradiations of human melanocytes with UVR-activated cPLA(2), the rate-limiting enzyme in eicosanoid synthesis and stimulated PGE(2) secretion. PGE(2) increased cAMP production, tyrosinase activity and proliferation in melanocytes. PGE(2) binds to four distinct G-protein coupled receptors (EP(1-4)). We show that PGE(2) stimulates EP(4) receptor signalling in melanocytes, resulting in cAMP production. Conversely, PGE(2) also stimulated the EP(3) receptor in melanocytes, resulting in lowered basal cAMP levels. These data suggest that relative levels or activity of these receptors controls effects of PGE(2) on cAMP in melanocytes. The data are the first to identify PGE(2) as an UVR-inducible autocrine factor for melanocytes. These data also show that PGE(2) activates EP(3) and EP(4) receptor signalling, resulting in opposing effects on cAMP production, a critical signalling pathway that regulates proliferation and melanogenesis in melanocytes.
Collapse
|
95
|
Leslie CC, Gangelhoff TA, Gelb MH. Localization and function of cytosolic phospholipase A2alpha at the Golgi. Biochimie 2010; 92:620-6. [PMID: 20226226 DOI: 10.1016/j.biochi.2010.03.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 03/04/2010] [Indexed: 11/17/2022]
Abstract
Cytosolic phospholipase A(2)alpha (cPLA(2)alpha, Group IVA phospholipase A(2)) is a central mediator of arachidonate release from cellular phospholipids for the biosynthesis of eicosanoids. cPLA(2)alpha translocates to intracellular membranes including the Golgi in response to a rise in intracellular calcium level. The enzyme's calcium-dependent phospholipid-binding C2 domain provides the targeting specificity for cPLA(2)alpha translocation to the Golgi. However, other features of cPLA(2)alpha regulation are incompletely understood such as the role of phosphorylation of serine residues in the catalytic domain and the function of basic residues in the cPLA(2)alpha C2 and catalytic domains that are proposed to interact with anionic phospholipids in the membrane to which cPLA(2)alpha is targeted. Increasing evidence strongly suggests that cPLA(2)alpha plays a role in regulating Golgi structure, tubule formation and intra-Golgi transport. For example, recent data suggests that cPLA(2)alpha regulates the transport of tight junction and adherens junction proteins through the Golgi to cell-cell contacts in confluent endothelial cells. However, there are now examples where data based on knockdown using siRNA or pharmacological inhibition of enzymatic activity of cPLA(2)alpha affects fundamental cellular processes yet these phenotypes are not observed in cells from cPLA(2)alpha deficient mice. These results suggest that in some cases there may be compensation for the lack of cPLA(2)alpha. Thus, there is continued need for studies employing highly specific cPLA(2)alpha antagonists in addition to genetic deletion of cPLA(2)alpha in mice.
Collapse
Affiliation(s)
- Christina C Leslie
- Department of Pediatrics, National Jewish Health, Denver, CO 80206, USA.
| | | | | |
Collapse
|
96
|
Rosenberger TA, Villacreses NE, Weis MT, Rapoport SI. Rat brain docosahexaenoic acid metabolism is not altered by a 6-day intracerebral ventricular infusion of bacterial lipopolysaccharide. Neurochem Int 2009; 56:501-7. [PMID: 20026368 DOI: 10.1016/j.neuint.2009.12.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 11/30/2009] [Accepted: 12/16/2009] [Indexed: 11/18/2022]
Abstract
In a rat model of neuroinflammation, produced by a 6-day intracerebral ventricular infusion of bacterial lipopolysaccharide (LPS), we reported that the brain concentrations of non-esterified brain arachidonic acid (AA, 20:4 n-6) and its eicosanoid products PGE(2) and PGD(2) were increased, as were AA turnover rates in certain brain phospholipids and the activity of AA-selective cytosolic phospholipase A(2) (cPLA(2)). The activity of Ca(2+)-independent iPLA(2), which is thought to be selective for the release of docosahexaenoic acid (DHA, 22:6 n-3) from membrane phospholipid, was unchanged. In the present study, we measured parameters of brain DHA metabolism in comparable artificial cerebrospinal fluid (control) and LPS-infused rats. In contrast to the reported changes in markers of AA metabolism, the brain non-esterified DHA concentration and DHA turnover rates in individual phospholipids were not significantly altered by LPS infusion. The formation rates of AA-CoA and DHA-CoA in a microsomal brain fraction were also unaltered by the LPS infusion. These observations indicate that LPS-treatment upregulates markers of brain AA but not DHA metabolism. All of which are consistent with other evidence that suggest different sets of enzymes regulate AA and DHA recycling within brain phospholipids and that only selective increases in brain AA metabolism occur following a 6-day LPS infusion.
Collapse
Affiliation(s)
- Thad A Rosenberger
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
| | | | | | | |
Collapse
|
97
|
Lamour NF, Subramanian P, Wijesinghe DS, Stahelin RV, Bonventre JV, Chalfant CE. Ceramide 1-phosphate is required for the translocation of group IVA cytosolic phospholipase A2 and prostaglandin synthesis. J Biol Chem 2009; 284:26897-907. [PMID: 19632995 PMCID: PMC2785377 DOI: 10.1074/jbc.m109.001677] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 07/20/2009] [Indexed: 12/16/2022] Open
Abstract
Little is known about the regulation of eicosanoid synthesis proximal to the activation of cytosolic phospholipase A(2)alpha (cPLA(2)alpha), the initial rate-limiting step. The current view is that cPLA(2)alpha associates with intracellular/phosphatidylcholine-rich membranes strictly via hydrophobic interactions in response to an increase of intracellular calcium. In opposition to this accepted mechanism of two decades, ceramide 1-phosphate (C1P) has been shown to increase the membrane association of cPLA(2)alpha in vitro via a novel site in the cationic beta-groove of the C2 domain (Stahelin, R. V., Subramanian, P., Vora, M., Cho, W., and Chalfant, C. E. (2007) J. Biol. Chem. 282, 20467-204741). In this study we demonstrate that C1P is a proximal and required bioactive lipid for the translocation of cPLA(2)alpha to intracellular membranes in response to inflammatory agonists (e.g. calcium ionophore and ATP). Last, the absolute requirement of the C1P/cPLA(2)alpha interaction was demonstrated for the production of eicosanoids using murine embryonic fibroblasts (cPLA(2)alpha(-/-)) coupled to "rescue" studies. Therefore, this study provides a paradigm shift in how cPLA(2)alpha is activated during inflammation.
Collapse
Affiliation(s)
- Nadia F. Lamour
- From the Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614
| | - Preeti Subramanian
- From the Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614
| | - Dayanjan S. Wijesinghe
- From the Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614
| | - Robert V. Stahelin
- the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, South Bend, Indiana 46617
- the Department of Chemistry and Biochemistry and Walther Center for Cancer Research, University of Notre Dame, South Bend, Indiana 46556
| | - Joseph V. Bonventre
- the Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Charles E. Chalfant
- From the Department of Biochemistry, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298-0614
- **Research and Development, Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Virginia 23249, and
- The Massey Cancer Center, Richmond, Virginia 23298
| |
Collapse
|
98
|
Zhou L, Choi HY, Li WP, Xu F, Herz J. LRP1 controls cPLA2 phosphorylation, ABCA1 expression and cellular cholesterol export. PLoS One 2009; 4:e6853. [PMID: 19718435 PMCID: PMC2729921 DOI: 10.1371/journal.pone.0006853] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 08/04/2009] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND ATP-binding cassette transporter A1 mediates apolipoprotein AI-dependent efflux of cholesterol and thereby removes cholesterol from peripheral tissues. ABCA1 expression is tightly regulated and deficiency of this cholesterol transporter results in cholesterol accumulation within cells. Low-density lipoprotein receptor-related protein 1 (LRP1) participates in lipid metabolism and energy homeostasis by endocytosis of apolipoprotein E-containing lipoproteins and modulation of cellular proliferation signals. METHODS AND PRINCIPAL FINDINGS In the present study, we demonstrate a new role for LRP1 in reverse cholesterol transport. Absence of LRP1 expression results in increased PDGFRbeta signaling and sequential activation of the mitogen-activated protein kinase signaling pathway, which increases phosphorylation of cytosolic phospholipase A(2) (cPLA(2)). Phosphorylated and activated cPLA(2) releases arachidonic acid from the phospholipid pool. Overproduction of arachidonic acid suppresses the activation of LXR/RXR heterodimers bound to the promoter of LXR regulated genes such as ABCA1, resulting in greatly reduced ABCA1 expression. CONCLUSIONS AND SIGNIFICANCE LRP1 regulates LXR-mediated gene transcription and participates in reverse cholesterol transport by controlling cPLA(2) activation and ABCA1 expression. LRP1 thus functions as a physiological integrator of cellular lipid homeostasis with signals that regulate cellular proliferation and vascular wall integrity.
Collapse
Affiliation(s)
- Li Zhou
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Hong Y. Choi
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Wei-Ping Li
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Fang Xu
- Department of Human Nutrition, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
| |
Collapse
|
99
|
Coupled calcium and zinc dyshomeostasis and oxidative stress in cardiac myocytes and mitochondria of rats with chronic aldosteronism. J Cardiovasc Pharmacol 2009; 53:414-23. [PMID: 19333130 DOI: 10.1097/fjc.0b013e3181a15e77] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A dyshomeostasis of extra- and intracellular Ca(2+) and Zn(2+) occurs in rats receiving chronic aldosterone/salt treatment (ALDOST). Herein, we hypothesized that the dyshomeostasis of intracellular Ca(2+) and Zn(2+) is intrinsically coupled that alters the redox state of cardiac myocytes and mitochondria, with Ca(2+) serving as a pro-oxidant and Zn(2+) as an antioxidant. Toward this end, we harvested hearts from rats receiving 4 weeks of ALDOST alone or cotreatment with either spironolactone (Spiro), an aldosterone receptor antagonist, or amlodipine (Amlod), an L-type Ca(2+) channel blocker, and from age/sex-matched untreated controls. In each group, we monitored cardiomyocyte [Ca(2+)]i and [Zn(2+)]i and mitochondrial [Ca(2+)]m and [Zn(2+)]m; biomarkers of oxidative stress and antioxidant defenses; expression of Zn transporters, Zip1 and ZnT-1; metallothionein-1, a Zn(2+)-binding protein; and metal response element transcription factor-1, a [Zn(2+)]i sensor and regulator of antioxidant defenses. Compared with controls, at 4-week ALDOST, we found the following: (a) increased [Ca(2+)]i and [Zn(2+)]i, together with increased [Ca(2+)]m and [Zn(2+)]m, each of which could be prevented by Spiro and attenuated with Amlod; (b) increased levels of 3-nitrotyrosine and 4-hydroxy-2-nonenal in cardiomyocytes, together with increased H(2)O(2) production, malondialdehyde, and oxidized glutathione in mitochondria that were coincident with increased activities of Cu/Zn superoxide dismutase and glutathione peroxidase; and (c) increased expression of metallothionein-1, Zip1 and ZnT-1, and metal response element transcription factor-1, attenuated by Spiro. Thus, an intrinsically coupled dyshomeostasis of intracellular Ca(2+) and Zn(2+) occurs in cardiac myocytes and mitochondria in rats receiving ALDOST, where it serves to alter their redox state through a respective induction of oxidative stress and generation of antioxidant defenses. The importance of therapeutic strategies that can uncouple these two divalent cations and modulate their ratio in favor of sustained antioxidant defenses is therefore suggested.
Collapse
|
100
|
Barnett JM, McCollum GW, Penn JS. Role of cytosolic phospholipase A(2) in retinal neovascularization. Invest Ophthalmol Vis Sci 2009; 51:1136-42. [PMID: 19661235 DOI: 10.1167/iovs.09-3691] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify and characterize the role of cytosolic phospholipase A(2) (cPLA(2)) in retinal angiogenesis using relevant cell-based assays and a rodent model of retinopathy of prematurity. METHODS The phosphorylation states of cPLA(2) and p38 MAP kinase and the expression of COX-2 were assessed by Western blot analysis in rat Müller cells. The activities of PLA(2) enzymes in rat retinal lysates were assessed using a commercially available assay. Prostaglandin E(2) (PGE(2)) and VEGF levels in Müller cell-conditioned medium and in retinal tissue samples were measured by ELISA. Rat retinal microvascular endothelial cell proliferation was measured using a BrdU assay. Efficacy of the cPLA(2) inhibitor CAY10502 was tested using the rat model of oxygen-induced retinopathy (OIR) in which neovascularization (NV) was assessed by computer-assisted image analysis. RESULTS In Müller cells, hypoxia increased the phosphorylation of cPLA(2) and p38 MAP kinase by 4-fold and 3-fold respectively. The cPLA(2) inhibitor CAY10502 decreased hypoxia-induced PGE(2) and VEGF levels in Müller cell-conditioned medium by 68.6% (P < 0.001) and 46.6% (P < 0.001), respectively. Retinal cPLA(2) activity peaked 1 day after oxygen exposure in OIR rats. CAY10502 (250 nM) decreased OIR-induced retinal PGE(2) and VEGF levels by 69% (P < 0.001) and 40.2% (P < 0.01), respectively. Intravitreal injection of 100 nM CAY10502 decreased retinal NV by 53.1% (P < 0.0001). CONCLUSIONS cPLA(2) liberates arachidonic acid, the substrate for prostaglandin (PG) production by the cyclooxygenase enzymes. PGs can exert a proangiogenic influence by inducing VEGF production and by stimulating angiogenic behaviors in vascular endothelial cells. Inhibition of cPLA(2) inhibits the production of proangiogenic PGs. Thus, cPLA(2) inhibition has a significant influence on pathologic retinal angiogenesis.
Collapse
Affiliation(s)
- Joshua M Barnett
- Vanderbilt Eye Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8808, USA
| | | | | |
Collapse
|