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Kusurkar RV, Rayani RH, Parmar DR, Patel DR, Patel MJ, Pandey NO, Zunjar V, Soni JY. Phenyl Substituted 3-Chloro 2-azetidinones: Design, Green Synthesis, Antimicrobial Activity, and Molecular Docking Studies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.134185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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2
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Design, Synthesis, In silico ADME Prediction Molecular Docking and Antitubercular Screening of Bromo-pyridyl tethered 3-Chloro 2-azetidinone Derivatives. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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3
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AYGÜN BETÜL, BERBER AHMETA, DOGANCI MERVEA, BERBER NURCAN, ŞEN SELEN, YILDIZ ESRA, AKSOY HÜSEYIN. Genotoxicity evaluation of a new phthalazine substituted β-lactam derivative in human lymphocytes. AN ACAD BRAS CIENC 2022; 94:e20191476. [DOI: 10.1590/0001-3765202120191476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/22/2020] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | - SELEN ŞEN
- Sakarya University of Applied Sciences, Turkey
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4
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Synthesis and biological evaluation of Schiff’s bases and 2-azetidinones of isonocotinyl hydrazone as potential antidepressant and nootropic agents. ARAB J CHEM 2016. [DOI: 10.1016/j.arabjc.2011.02.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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5
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Chen X, Xu W, Wang K, Mo M, Zhang W, Du L, Yuan X, Xu Y, Wang Y, Shen J. Discovery of a Novel Series of Imidazo[1,2-a]pyrimidine Derivatives as Potent and Orally Bioavailable Lipoprotein-Associated Phospholipase A2 Inhibitors. J Med Chem 2015; 58:8529-41. [DOI: 10.1021/acs.jmedchem.5b01024] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Xinde Chen
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Wenwei Xu
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Kai Wang
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Mingguang Mo
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Wei Zhang
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Lili Du
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiaojing Yuan
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yechun Xu
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yiping Wang
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jianhua Shen
- State Key Laboratory of Drug
Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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Zeng L, Yan J, Luo L, Zhang D. Effects of Pu-erh tea aqueous extract (PTAE) on blood lipid metabolism enzymes. Food Funct 2015; 6:2008-16. [DOI: 10.1039/c5fo00362h] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Effects of Pu-erh tea aqueous extract (PTAE) on blood lipid metabolism enzymes (e.g.HMGR) are assayedin vitro.
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Affiliation(s)
- Liang Zeng
- College of Food Science
- Southwest University
- Chongqing
- China
- TAETEA Group Postdoctoral Research Station
| | - Jingna Yan
- College of Food Science
- Southwest University
- Chongqing
- China
| | - Liyong Luo
- College of Food Science
- Southwest University
- Chongqing
- China
| | - Dongying Zhang
- College of Longrun Pu-erh Tea
- Yunnan Agricultural University
- Kunming
- China
- TAETEA Group Postdoctoral Research Station
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Abstract
Although an atherogenic lipoprotein phenotype has been well recognized as an important predictor of cardiovascular disease, recent studies have demonstrated a number of additional lipid-related markers as emerging biomarkers to identify patients at risk for future coronary heart disease. Among them, lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), seems to be a promising candidate that might be added to the clinical armamentarium for improved prediction of cardiovascular disease in the future. Of particular note, Lp-PLA(2) is the only enzyme that cleaves oxidized low-density lipoprotein (oxLDL) in the subendothelial space, with further generation of proinflammatory mediators such as lysophosphatidylcholine (LysoPC) and oxidized fatty acid (oxFA), thereby probably linking two important features of atherogenesis, namely oxidation of LDL and local inflammatory processes within the atherosclerotic plaque. This overview aims to summarize our current knowledge based on observations from recent experimental and clinical studies. Emphasis has been put on potential pathophysiological mechanisms of action and on the clinical relevance of Lp-PLA(2) in a wide variety of clinical settings, including apparently healthy individuals, patients with stable angina or acute coronary syndromes, after myocardial infarction, and with subclinical disease. Although a growing body of evidence from epidemiological and clinical studies suggests that Lp-PLA(2) may represent an independent and clinically relevant long-term risk marker for coronary heart disease and, probably, also for stroke, the role of this enzyme in the setting of the acute coronary syndrome remains to be established.
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Affiliation(s)
- Natalie Khuseyinova
- Department of Internal Medicine II - Cardiology, University of Ulm Medical Center, Ulm, Germany
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Lin EC, Hu Y, Amantea CM, Pham LM, Cajica J, Okerberg E, Brown HE, Fraser A, Du L, Kohno Y, Ishiyama J, Kozarich JW, Shreder KR. Amides of xanthurenic acid as zinc-dependent inhibitors of Lp-PLA2. Bioorg Med Chem Lett 2012; 22:868-71. [DOI: 10.1016/j.bmcl.2011.12.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 12/05/2011] [Accepted: 12/08/2011] [Indexed: 10/14/2022]
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9
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Dennis EA, Cao J, Hsu YH, Magrioti V, Kokotos G. Phospholipase A2 enzymes: physical structure, biological function, disease implication, chemical inhibition, and therapeutic intervention. Chem Rev 2011; 111:6130-85. [PMID: 21910409 PMCID: PMC3196595 DOI: 10.1021/cr200085w] [Citation(s) in RCA: 802] [Impact Index Per Article: 61.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward A. Dennis
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Jian Cao
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Yuan-Hao Hsu
- Department of Chemistry and Biochemistry and Pharmacology, School of Medicine, University of California, San Diego, La Jolla, California 92093-0601
| | - Victoria Magrioti
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
| | - George Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
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Mitsutake R, Miura SI, Zhang B, Saku K. HDL-associated factors provide additional prognostic information for coronary artery disease as determined by multi-detector row computed tomography. Int J Cardiol 2010; 143:72-8. [DOI: 10.1016/j.ijcard.2009.01.058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 01/15/2009] [Accepted: 01/23/2009] [Indexed: 01/07/2023]
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Lipoprotein-Associated Phospholipase A2 and C-Reactive Protein for Measurement of Inflammatory Risk: Independent or Complementary? CURRENT CARDIOVASCULAR RISK REPORTS 2009. [DOI: 10.1007/s12170-009-0073-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Davis B, Koster G, Douet LJ, Scigelova M, Woffendin G, Ward JM, Smith A, Humphries J, Burnand KG, Macphee CH, Postle AD. Electrospray Ionization Mass Spectrometry Identifies Substrates and Products of Lipoprotein-associated Phospholipase A2 in Oxidized Human Low Density Lipoprotein. J Biol Chem 2008; 283:6428-37. [DOI: 10.1074/jbc.m709970200] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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13
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Möckel M, Müller R, Vollert JO, Müller C, Danne O, Gareis R, Störk T, Dietz R, Koenig W. Lipoprotein-associated phospholipase A2 for early risk stratification in patients with suspected acute coronary syndrome: a multi-marker approach: the North Wuerttemberg and Berlin Infarction Study-II (NOBIS-II). Clin Res Cardiol 2007; 96:604-12. [PMID: 17593313 DOI: 10.1007/s00392-007-0540-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Accepted: 04/25/2007] [Indexed: 11/28/2022]
Abstract
AIMS Numerous markers have been identified as useful predictors of major adverse cardiac events (MACE) in patients with suspected acute coronary syndrome (ACS). However, only little is known about the relative benefit of the single markers in risk stratification and the best combination for optimising prognostic power. The aim of the present study was to define the role of the emerging cardiovascular risk marker lipoprotein-associated phospholipase A2 (Lp-PLA2) in a multi-marker approach in combination with troponin I (TnI), NT-proBNP, high sensitivity (hs)CRP, and D-dimer in patients with ACS. METHODS AND RESULTS A total of 429 consecutive patients (age 60.5+/-14.1 years, 60.6% male) who were admitted to the emergency room with suspected ACS were analysed in the study. Biochemical markers were measured by immunoassay techniques. All patients underwent point-of-care TnI testing and early coronary angiography if appropriate, in accordance with the current guidelines. Classification and regression trees (CART) and logistic regression techniques were employed to determine the relative predictive power of markers for the primary end-point defined as any of the following events within 42 days after admission: death, non-fatal myocardial infarction, unstable AP requiring admission, admission for decompensated heart failure or shock, percutaneous coronary intervention, coronary artery bypass grafting, life threatening arrhythmias or resuscitation. The incidence of the primary end-point was 13.1%, suggesting a mild to moderate risk population. The best overall risk stratification was obtained using NT-proBNP at a cut-off of 5000 pg/mL (incidence of 40% versus 10.3%, relative risk (RR) 3.9 (95% CI 2.4-6.3)). In the remaining lower risk group with an incidence of 10.3%, further separation was performed using TnI (cut-off 0.14 microg/L; RR=3.1 (95% CI 1.7-5.5) 23.2% versus 7.5%) and again NT-proBNP (at a cut-off of 140 ng/L) in patients with negative TnI (RR=3.2 (95% CI 1.3-7.9), 11.7% versus 3.6%). A final significant stratification in patients with moderately elevated NT-proBNP levels was achieved using Lp-PLA2 at a cut-off of 210 microg/L) (17.9% versus 6.9%; RR=2.6 (95% CI 1.1-6.6)). None of the clinical or ECG variables of the TIMI (Thrombolysis In Myocardial Infarction) risk score provided comparable clinically relevant information for risk stratification. CONCLUSIONS In the setting of stateof- the-art coronary care for patients with suspected ACS in the emergency room, NT-proBNP, troponin I, and Lp-PLA2 are effective independent markers for risk stratification that proved to be superior to the TIMI risk score. Lp-PLA2 turned out to be a more effective risk marker than hsCRP in these patients.
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Affiliation(s)
- M Möckel
- Dept. of Cardiology, Charité - University Medicine Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353, Berlin, Germany.
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Virani SS, Nambi V. The role of lipoprotein-associated phospholipase A2 as a marker for atherosclerosis. Curr Atheroscler Rep 2007; 9:97-103. [PMID: 17877917 DOI: 10.1007/s11883-007-0004-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that belongs to the superfamily of phospholipase A2 enzymes. Although initial studies showed that Lp-PLA2 might be protective against atherosclerosis, emerging data seem to suggest that Lp-PLA2 may be proatherogenic, which is an effect thought to be mediated by lysophosphatidylcholine and oxidized nonesterified fatty acids, two mediators generated by Lp-PLA2. This article reviews the potential mechanisms by which Lp-PLA2 may participate in the pathogenesis of atherosclerosis and its clinical manifestations, namely, coronary artery disease and stroke.
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Affiliation(s)
- Salim S Virani
- Department of Medicine, Baylor College of Medicine, 6565 Fannin, M.S. A-601, Houston, TX 77030, USA
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15
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Ballantyne CM. Lipoprotein-associated phospholipase A2: Risk marker or target of therapy? CURRENT CARDIOVASCULAR RISK REPORTS 2007. [DOI: 10.1007/s12170-007-0011-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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16
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Karasawa K. Clinical aspects of plasma platelet-activating factor-acetylhydrolase. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1359-72. [PMID: 17049457 DOI: 10.1016/j.bbalip.2006.06.017] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Accepted: 06/15/2006] [Indexed: 11/25/2022]
Abstract
Plasma platelet-activating factor (PAF)-acetylhydrolase (PAF-AH), which is characterized by tight association with plasma lipoproteins, degrades not only PAF but also phospholipids with oxidatively modified short fatty acyl chain esterified at the sn-2 position. Production and accumulation of these phospholipids are associated with the onset of inflammatory diseases and preventive role of this enzyme has been evidenced by many recent studies including prevalence of the genetic deficiency of the enzyme in the patients and therapeutic effects of treatment with recombinant protein or gene transfer. With respect to the atherosclerosis, however, it is not fully cleared whether this enzyme plays an anti-atherogenic role or pro-atherogenic role because plasma PAF-AH also might produce lysophosphatidylcholine (LysoPC) and oxidatively modified nonesterified fatty acids with potent pro-inflammatory and pro-atherogenic bioactivities. These dual roles of plasma PAF-AH might be regulated by the altered distribution of the enzyme between low density lipoprotein (LDL) and high density lipoprotein (HDL) particles because HDL-associated enzymes are considered to contribute to the protection of LDL from oxidative modification. This review focuses on the recent findings which address the role of this enzyme in the human diseases especially including asthma, septic shock and atherosclerosis.
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Affiliation(s)
- Ken Karasawa
- Laboratory of Molecular Pharmaceutics, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamihara, Kanagawa 199-0195, Japan.
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Nambi V, Ballantyne CM. Lipoprotein-associated phospholipase A2: Pathogenic mechanisms and clinical utility for predicting cardiovascular events. Curr Atheroscler Rep 2006; 8:374-81. [PMID: 16901407 DOI: 10.1007/s11883-006-0034-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipoprotein-associated phospholipase A(2 )(Lp-PLA(2)), a member of the phospholipase superfamily, circulates primarily bound to low-density lipoprotein and has been associated with cardiovascular disease risk in epidemiologic studies. However, it has not been established whether Lp-PLA(2) is a risk marker or a risk factor. Identification of individuals with elevated Lp-PLA(2) may improve risk assessment, and Lp-PLA(2) may also provide an additional target of therapy. Statin therapy has been shown to reduce Lp-PLA(2), and selective inhibitors of Lp-PLA(2) are under development. Additional research is needed to further determine the role of Lp-PLA(2) in atherogenesis and atherothrombotic events.
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Affiliation(s)
- Vijay Nambi
- Section of Cardiology, Baylor College of Medicine, 6550 Fannin, SM 677, Houston, TX 77030, USA.
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Zhang FJ, Cai MJ, Shen JK, Wang YP. Expression and purification of lipoprotein-associated phospholipase A(2), a key enzyme involved in atherosclerosis. Acta Pharmacol Sin 2006; 27:679-84. [PMID: 16723085 DOI: 10.1111/j.1745-7254.2006.00308.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To express and purify lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), and to establish a screening model for Lp-PL A(2) inhibitors using the expressed Lp-PLA(2). METHODS We cloned the full-length cDNA of Lp-PLA(2) from differentiated THP-1 cells, and subcloned the cDNA into the baculovirus transfer vector pFastBac1. In addition, we introduced an N-terminal Kozak sequence for high-level translation initiation and a C-terminal sequence of 6 histidine residues for purification. The fusion enzyme was expressed in Sf9 insect cells and purified by Ni(2+) affinity chromatography. Recombinant Lp-PLA(2) activity was measured using [(3)H]PAF as a substrate, and we examined the enzyme activity of recombinant Lp-PLA(2) pretreated with the known Lp-PLA(2) inhibitor SB435495. RESULTS We successfully cloned the full-length Lp-PLA(2) gene from differentiated THP-1 cells. The fusion enzyme was expressed in Sf9 insect cells at a high level and purified efficiently through a 2-step procedure. The recombinant Lp-PLA(2) activity was measured using [(3)H]PAF as a substrate, and proved to be enzymatically active. Lp-PLA(2) inhibitor SB435495 produced a good inhibition curve for inhibition of recombinant Lp-PLA(2) with an IC(50) of 57+/-1 micromol/L. CONCLUSION We expressed and purified Lp-PLA(2) at a high level in insect cell-baculovirus expression system. The yield ratio was much greater than that obtained from human plasma and we established a screening model for Lp-PL A(2) inhibitors using the expressed Lp-PLA(2).
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Affiliation(s)
- Fu-Jun Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201203, China
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19
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Zhang F, Wang Y. Cloning, expression, and purification of lipoprotein-associated phospholipase A(2) in Pichia pastoris. Mol Biotechnol 2006; 33:29-36. [PMID: 16691004 DOI: 10.1385/mb:33:1:29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has been shown to play a crucial role in atherosclerosis, and has been proposed as a promising target for drug discovery. Here, we cloned the Lp-PLA(2) gene from differentiated THP-1 cells, and inserted a carboxy-terminal His(6)-tagged version of the gene into the pPIC9 Pichia expression vector. The Lp-PLA(2) fusion protein was successfully expressed in Pichia pastoris expression system and could be rapidly purified to apparent homogeneity using a single-step purification method. The activity of our recombinant Lp-PLA(2) was strong when [3H] PAF was used as a substrate, and the Lp-PLA(2) inhibitor SB435495 exhibited an inhibitory curve against the recombinant Lp-PLA2 (IC50 = 15.93 +/- 1 microM). This novel recombinant Lp-PLA(2) could prove useful as a screening model for Lp-PLA(2) inhibitors, and may facilitate further investigation of this protein in atherosclerosis.
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Affiliation(s)
- Fujun Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Graduate School, Chinese Academy of Sciences, Shanghai 201203, China
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Koenig W, Twardella D, Brenner H, Rothenbacher D. Lipoprotein-associated phospholipase A2 predicts future cardiovascular events in patients with coronary heart disease independently of traditional risk factors, markers of inflammation, renal function, and hemodynamic stress. Arterioscler Thromb Vasc Biol 2006; 26:1586-93. [PMID: 16627803 DOI: 10.1161/01.atv.0000222983.73369.c8] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE We sought to evaluate whether lipoprotein-associated phospholipase A2 (Lp-PLA2), an emerging marker of cardiovascular risk, is associated with prognosis in patients with coronary heart disease (CHD). METHODS AND RESULTS Plasma concentrations and activity of Lp-PLA2 were determined in 1051 patients aged 30 to 70 years with CHD who were followed for &4 years. A Cox proportional hazards model was used to determine the prognostic value of Lp-PLA2 after adjustment for various covariates, including markers of inflammation, renal function, and hemodynamic stress. In multivariable analyses, Lp-PLA2 mass and activity were strongly associated with cardiovascular events after controlling for traditional risk factors, severity of CHD, statin treatment, cystatin C, and N-terminal proBNP. The hazard ratio (HR) for recurrent events was 2.65 (95% confidence interval [CI], 1.47 to 4.76) for the top tertile of Lp-PLA2 mass compared with the bottom tertile and 2.40 (95% CI, 1.35 to 4.29) for Lp-PLA2 activity. After additional adjustment for low-density lipoprotein (LDL), the HRs were only moderately attenuated (mass: 2.09; 95% CI, 1.10 to 3.96; activity: 1.81; 95% CI, 0.94 to 3.49, respectively), but the latter was no longer statistically significant. CONCLUSIONS Increased concentrations of Lp-PLA2 predict future cardiovascular events in patients with manifest CHD independent of a variety of potential risk factors including markers of inflammation, renal function, and hemodynamic stress.
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Affiliation(s)
- Wolfgang Koenig
- Department of Internal Medicine II-Cardiology, University of Ulm Medical Center, Robert-Koch Str. 8, D-89081 Ulm, Germany.
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Zhang F, Dong L, Cai M, Shen J, Wang Y. Heterologous expression of lipoprotein-associated phospholipase A2 in different expression systems. Protein Expr Purif 2006; 48:300-6. [PMID: 16682228 DOI: 10.1016/j.pep.2006.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Revised: 03/18/2006] [Accepted: 03/21/2006] [Indexed: 11/24/2022]
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a key enzyme involved in atherosclerosis, and has been considered as a new target for drug discovery. The major difficulty for high-throughput screening of Lp-PLA(2) inhibitors and for functional studies was their fast and efficient production. Purification of native Lp-PLA(2) from human plasma was complicated and produced a very low yield. We herein examined the feasibility of expressing and purifying recombinant Lp-PLA(2) in different heterologous expression systems. The fusion Lp-PLA(2) was expressed at high levels and exhibited strong enzyme activity in insect cell-baculovirus expression system. The functional enzyme could also be produced in Pichia pastoris. The inclusion of a Kozak sequence increased greatly the expression level of recombinant Lp-PLA(2) in insect cells, but had little effect on the expression of recombinant Lp-PLA(2) in P. pastoris and Escherichia coli. P. pastoris-produced Lp-PLA(2) could be purified rapidly and conveniently through a one-step procedure, while baculovirus-produced Lp-PLA(2) could be efficiently purified through a two-step procedure. This ability to readily produce recombinant Lp-PLA(2) could provide a screening model for Lp-PLA(2) inhibitors and will facilitate further studies on this enzyme.
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Affiliation(s)
- Fujun Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
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22
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Stafforini DM, Sheller JR, Blackwell TS, Sapirstein A, Yull FE, McIntyre TM, Bonventre JV, Prescott SM, Roberts LJ. Release of free F2-isoprostanes from esterified phospholipids is catalyzed by intracellular and plasma platelet-activating factor acetylhydrolases. J Biol Chem 2005; 281:4616-23. [PMID: 16371369 DOI: 10.1074/jbc.m507340200] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
F2-isoprostanes are produced in vivo by nonenzymatic peroxidation of arachidonic acid esterified in phospholipids. Increased urinary and plasma F2-isoprostane levels are associated with a number of human diseases. These metabolites are regarded as excellent markers of oxidant stress in vivo. Isoprostanes are initially generated in situ, i.e. when the arachidonate precursor is esterified in phospholipids, and they are subsequently released in free form. Although the mechanism(s) responsible for the release of free isoprostanes after in situ generation in membrane phospholipids is, for the most part, unknown, this process is likely mediated by phospholipase A2 activity(ies). Here we reported that human plasma contains an enzymatic activity that catalyzes this reaction. The activity associates with high density and low density lipoprotein and comigrates with platelet-activating factor (PAF) acetylhydrolase on KBr density gradients. Plasma samples from subjects deficient in PAF acetylhydrolase do not release F2-isoprostanes from esterified precursors. The intracellular PAF acetylhydrolase II, which shares homology to the plasma enzyme, also catalyzes this reaction. We found that both the intracellular and plasma PAF acetylhydrolases have high affinity for esterified F2-isoprostanes. However, the rate of esterified F2-isoprostane hydrolysis is much slower compared with the rate of hydrolysis of other substrates utilized by these enzymes. Studies using PAF acetylhydrolase transgenic mice indicated that these animals have a higher capacity to release F2-isoprostanes compared with nontransgenic littermates. Our results suggested that PAF acetylhydrolases play key roles in the hydrolysis of F2-isoprostanes esterified on phospholipids in vivo.
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Affiliation(s)
- Diana M Stafforini
- Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112-5550, USA.
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Abstract
Because biomarkers of myocardial necrosis only become positive in the setting of myocardial necrosis and disruption of cellular integrity, the diagnosis of myocardial infarction can only be made in retrospect. Ideally, one would like to identify patients at risk for complications before myocardial necrosis occurs. Insights into the pathophysiology of atherothrombosis have allowed development of novel markers to detect not only early ischemia without myocyte death but also early indicators of coronary inflammation inpatients who have preclinical atherosclerosis.
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Affiliation(s)
- Tracy Y Wang
- Division of Cardiology, Duke University Medical Center, Durham, NC 27710, USA
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24
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Caslake MJ, Packard CJ. Lipoprotein-associated phospholipase A2 as a biomarker for coronary disease and stroke. ACTA ACUST UNITED AC 2005; 2:529-35. [PMID: 16186851 DOI: 10.1038/ncpcardio0321] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Accepted: 06/27/2005] [Indexed: 11/08/2022]
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), also known as platelet-activating factor acetylhydrolase, is a plasma enzyme that circulates bound to lipoproteins. The association between Lp-PLA(2) and atherosclerosis is ambiguous, as it can both degrade and generate potentially damaging vasoactive molecules. In this article, we speculate that Lp-PLA(2) associated with HDL might have cardioprotective properties, whereas the same enzyme bound to LDL might contribute directly to atherosclerosis at all stages, from lipoprotein oxidation to endothelial dysfunction, and plaque initiation and growth. Genetic and animal model studies give varying indications as to the contribution of Lp-PLA(2) to atherogenesis and tend to support the view that higher Lp-PLA(2) levels are cardioprotective. By contrast, a series of population studies point clearly to a positive association between plasma Lp-PLA(2) levels or activity levels and risk of coronary heart disease or stroke. Typically, people with Lp-PLA(2) levels in the highest quintile of the population have about a twofold greater risk than those in the lowest quintile. It is, perhaps, too early to introduce Lp-PLA(2) as a population-wide biomarker for coronary heart disease risk; however, with accumulating evidence, it might find a place in a stepwise risk assessment of individuals who require more aggressive intervention to prevent vascular disease.
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25
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Lee JH, Cho KH, Lee KT, Kim MR. Antiatherogenic effects of structured lipid containing conjugated linoleic acid in C57BL/6J mice. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:7295-301. [PMID: 16131145 DOI: 10.1021/jf050626e] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Conjugated linoleic acids (CLA) were enzymatically acidolyzed with olive oil to produce structured lipids (SL), and their antiatherosclerotic properties were investigated in C57BL/6J mice. Twenty-eight mice were divided into four groups and fed control diet or atherogenic diets supplemented with high cholesterol and high fat (HCHF) containing 5% of lard, olive oil, or SL based on control diet for 4 weeks. The supplementation of SL diet (0.6% CLA) significantly reduced the levels of serum total cholesterol and total triglyceride and increased high-density lipoprotein cholesterol level as compared to lard and olive oil diet groups (p < 0.05). The activity of liver acyl CoA:cholesterol acyltransferase (ACAT) of mice fed the SL diet was significantly lower than that of mice fed the lard or olive oil diet. A reduced formation of aortic fatty streak was observed in SL group. The extent of CLA incorporation depended on tissues or types of phospholipids. More CLA was incorporated in adipose tissue (1.85 mol %) than in the liver (0.33 mol %). Besides, more CLA was found in phosphatidylethanolamine (PE) (0.47 mol %) than in phosphatidylcholine (PC) (0.05 mol %) of hepatic phospholipids. Hepatic phospholipids (PC and PE) of mice fed the SL diet contained reduced contents of arachidonic and linoleic acid compared with mice fed the olive oil or lard diet. The present study suggests that SL could be considered as a functional oil for preventing risks of atheroscelerosis.
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Affiliation(s)
- Jeung Hee Lee
- Department of Food Science and Nutrition, Chungnam National University, 220 Gung-Dong, Yusung-Gu, Daejeon, Korea
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26
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Lee WS, Kim MJ, Beck YI, Park YD, Jeong TS. Lp-PLA2 inhibitory activities of fatty acid glycerols isolated from Saururus chinensis roots. Bioorg Med Chem Lett 2005; 15:3573-5. [PMID: 15961310 DOI: 10.1016/j.bmcl.2005.05.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 05/03/2005] [Accepted: 05/16/2005] [Indexed: 11/23/2022]
Abstract
(R)-Glycerol-monolinoleate 4 and (R)-glycerol-monostearate 5 were isolated from the ethyl acetate extracts of Saururus chinensis roots and (R)- or (S)-fatty acid glycerols 4 and 5 were synthesized for confirming their structures and evaluating their inhibitory activities against Lp-PLA(2). The (R)-4 and (S)-4 exhibited Lp-PLA(2) inhibitory activities with IC(50) values of 45.0 and 52.0 microM, respectively.
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Affiliation(s)
- Woo Song Lee
- National Research Laboratory of Lipid Metabolism and Atherosclerosis, Korea Research Institute of Bioscience and Biotechnology, 52 Oun, Yusong, Daejeon 305-333, Republic of Korea
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27
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Kim DH, Jung SJ, Chung IS, Lee YH, Kim DK, Kim SH, Kwon BM, Jeong TS, Park MH, Seoung NS, Baek NI. Ergosterol Peroxide from Flowers of Erigeron annuus L. as an Anti-Atherosclerosis Agent. Arch Pharm Res 2005; 28:541-5. [PMID: 15974439 DOI: 10.1007/bf02977755] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Flowers of Erigeron annuus L. were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH, and H2O. Repeated silica gel and ODS column chromatography of the EtOAc fraction led to the isolation of a sterol, through activity-guided fractionation, using ACAT inhibitory activity measurements. From the physico-chemical data, including NMR, MS, and IR, the chemical structure of the compound was determined to be an ergosterol peroxide (1), which has been isolated for the first time from this plant. This compound exhibited hACAT-1 and Lp-PLA2 inhibitory effects, with inhibitory values of 51.6 +/- 0.9 and 51.7 +/- 1.2%, at a treatment concentration of 0.23 mM.
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Affiliation(s)
- Dong-Hyun Kim
- Graduate School of Biotechnology & Plant Metabolism Research Center, Kyung Hee University, Suwon 449-701, Korea
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28
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Khuseyinova N, Imhof A, Rothenbacher D, Trischler G, Kuelb S, Scharnagl H, Maerz W, Brenner H, Koenig W. Association between Lp-PLA2 and coronary artery disease: focus on its relationship with lipoproteins and markers of inflammation and hemostasis. Atherosclerosis 2005; 182:181-8. [PMID: 16115490 DOI: 10.1016/j.atherosclerosis.2004.10.046] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 10/19/2004] [Accepted: 10/21/2004] [Indexed: 11/24/2022]
Abstract
Lipoprotein-associated phospholipase A2 (Lp-PLA2) generates pro-inflammatory molecules from oxidized LDL. We examined the association between Lp-PLA2 plasma concentrations and risk of stable coronary artery disease (CAD) in a large case-control study and further assessed the relationship between Lp-PLA2 and various lipid, inflammatory and hemostatic parameters. Lp-PLA2 concentrations were measured in 312 patients with CAD and in 479 age- and gender-matched blood donors. Various sensitive inflammatory and hemostatic markers and a complete lipoprotein profile were obtained. Lp-PLA2 concentrations were significantly higher in cases than in controls (296.1 ng/mL versus 266.0 ng/mL, p<0.0001). In multivariable logistic regression, the age- and gender-adjusted OR for the presence of CAD was 1.61 (95% CI, 1.07-2.44) if the top quartile of the Lp-PLA2 distribution was compared to the bottom quartile. Adjustment for traditional cardiovascular risk factors and statin use resulted in an OR of 2.04 (95% CI, 1.19-3.48). After additional controlling for vWF, the OR was slightly attenuated but still remained statistically significant (OR 1.91; 95% CI, 1.12-3.28). Thus, elevated Lp-PLA2 concentrations were associated with the presence of stable CAD, independent of various biochemical markers. Our results support the hypothesis that Lp-PLA2 may be a novel, independent risk marker for CAD.
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Affiliation(s)
- Natalie Khuseyinova
- Department of Internal Medicine II, Cardiology, University of Ulm Medical Center, Robert-Koch Str. 8, D-89081 Ulm, Germany
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29
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Jeong TS, Kim MJ, Yu H, Kim KS, Choi JK, Kim SS, Lee WS. (E)-Phenyl- and -heteroaryl-substituted O-benzoyl-(or acyl)oximes as lipoprotein-associated phospholipase A2 inhibitors. Bioorg Med Chem Lett 2005; 15:1525-7. [PMID: 15713421 DOI: 10.1016/j.bmcl.2004.11.063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 11/25/2004] [Accepted: 11/25/2004] [Indexed: 10/26/2022]
Abstract
A series of (E)-phenyl- and -heteroaryl-substituted O-benzoyl- (or acyl)oximes 3a-n were synthesized for evaluating their human lipoprotein-associated phospholiphase A2 (Lp-PLA2) inhibitory activities. The less lipophilic derivatives 3a-c showed the most potent in vitro inhibitory activity on human Lp-PLA2.
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Affiliation(s)
- Tae-Sook Jeong
- National Research Laboratory of Lipid Metabolism and Atherosclerosis, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333, Republic of Korea
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30
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Koenig W, Khuseyinova N, Löwel H, Trischler G, Meisinger C. Lipoprotein-Associated Phospholipase A
2
Adds to Risk Prediction of Incident Coronary Events by C-Reactive Protein in Apparently Healthy Middle-Aged Men From the General Population. Circulation 2004; 110:1903-8. [PMID: 15451783 DOI: 10.1161/01.cir.0000143377.53389.c8] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Background—
Chronic inflammation represents an essential feature of the atherosclerotic process. Lipoprotein-associated phospholipase A
2
(Lp-PLA
2
), an enzyme mainly produced by monocytes/macrophages, generates potent proinflammatory products.
Methods and Results—
Plasma concentrations of Lp-PLA
2
were determined by ELISA in 934 apparently healthy men aged 45 to 64 years sampled from the general population in 1984 and followed up until 1998. During this period, 97 men experienced a coronary event diagnosed according to the MONICA (MONItoring of trends and determinants in CArdiovascular disease) protocol. Baseline levels of Lp-PLA
2
were higher in subjects who experienced an event than in event-free subjects (295±113 versus 263±79 ng/mL,
P
<0.01). Lp-PLA
2
was positively correlated with total cholesterol (
R
=0.30,
P
<0.0001) and age (
R
=0.12,
P
=0.001), was only slightly correlated with HDL cholesterol (
R
=0.09,
P
=0.005) and C-reactive protein
R
=0.06,
P
=0.06), but was not correlated with body mass index or blood pressure. In a Cox model, a 1-SD increase in Lp-PLA
2
was associated with risk of future coronary events (hazard ratio [HR] 1.37, 95% CI 1.16 to 1.62). After controlling for potential confounders, the HR was attenuated but remained statistically significant (HR 1.23, 95% CI 1.02 to 1.47). Further inclusion of C-reactive protein in the model did not appreciably affect its predictive ability (HR 1.21, 95% CI 1.01 to 1.45).
Conclusions—
Elevated levels of Lp-PLA
2
appeared to be predictive of future coronary events in apparently healthy middle-aged men with moderately elevated total cholesterol, independent of CRP. This suggests that Lp-PLA
2
and CRP may be additive in their ability to predict risk of coronary heart disease.
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Affiliation(s)
- Wolfgang Koenig
- Department of Internal Medicine II-Cardiology, University of Ulm Medical Center, Robert-Koch Strasse. 8, D-89081 Ulm, Germany.
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31
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Wu X, Zimmerman GA, Prescott SM, Stafforini DM. The p38 MAPK pathway mediates transcriptional activation of the plasma platelet-activating factor acetylhydrolase gene in macrophages stimulated with lipopolysaccharide. J Biol Chem 2004; 279:36158-65. [PMID: 15215249 DOI: 10.1074/jbc.m402454200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Administration of lipopolysaccharide (LPS) to experimental animals results in the up-regulation of expression of the plasma form of platelet-activating factor acetylhydrolase (PAF AH) in tissue macrophages. To investigate the mechanism underlying induction of PAF AH by LPS we used murine RAW264.7 and human THP-1 macrophages as model systems. We found that the p38 mitogen-activated protein kinase (p38 MAPK) pathway mediates transcriptional activation of the PAF AH gene through the participation of nucleotides -68/-316 relative to the transcriptional initiation site. This promoter region spans two Sp1/Sp3 binding sites (SP-A and SP-B) and is necessary and sufficient for the observed effect. Disruption of these Sp binding sites significantly reduces promoter activity in LPS-stimulated cells. The ability of LPS to induce transcriptional activation of PAF AH is not due to enhanced Sp1/Sp3 binding to the promoter but involves enhanced transactivation function of Sp1 via p38 MAPK activation. These studies characterize the mechanism by which LPS modulates expression of PAF AH at the transcriptional level, and they have important implications for our understanding of responses that occur during the development of LPS-mediated inflammatory diseases.
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Affiliation(s)
- Xiaoqing Wu
- Huntsman Cancer Institute and the Department of Oncological Sciences , University of Utah, Salt Lake City, Utah 84112, USA
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32
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McCarty MF. An elevation of triglycerides reflecting decreased triglyceride clearance may not be pathogenic – relevance to high-carbohydrate diets. Med Hypotheses 2004; 63:1065-73. [PMID: 15504577 DOI: 10.1016/j.mehy.2002.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2002] [Accepted: 11/11/2002] [Indexed: 01/26/2023]
Abstract
The fact that carbohydrate-rich diets often increase plasma triglycerides has led some to question the wisdom of such diets. This increase is primarily attributable to a decrease in the efficiency of triglyceride clearance -- whereas the elevation of triglycerides observed in insulin-resistant subjects stems mainly from increased hepatic production of VLDL particles. There is growing reason to suspect that the increased coronary risk associated with elevated triglycerides in Western epidemiology reflects the fact that high triglycerides are a marker for insulin resistance syndrome, rather than any inherent pathogenic role of triglycerides per se. Thus, endothelial dysfunction is seen only in those hypertriglyceridemic subjects who are insulin resistant, and is absent in patients whose markedly elevated triglycerides reflect genetically defective lipoprotein lipase activity. Triglyceride levels are relatively high in certain Third World societies which are virtually immune to coronary disease so long as they persist in their traditional very-low-fat diets; in Ornish's celebrated study, a moderate rise in triglycerides coincided with a marked reduction in coronary events. Although the particle size of both LDL and HDL tends to decrease when triglyceride levels are high, it is questionable whether this effect has a major pathogenic impact. The one clear drawback of high-carbohydrate diets is a decrease in HDL particle number, resulting from decreased hepatic production of apoA-I; this effect is seen whether or not triglycerides increase. The very favorable effects of very-low-fat, whole food, quasi-vegan diets on LDL cholesterol, insulin sensitivity, and body weight appear to more than compensate for this decrease in HDL; it is notable that HDL levels tend to be quite low in Third World cultures at minimal risk for coronary disease. On the other hand, this decrease in HDL may be of more significance in the context of omnivore diets only moderately low in fat, as suggested by the fact that diets higher in unsaturated fats emerge as more protective in Western prospective epidemiology. The tendency of high-carbohydrate diets to boost triglycerides can be minimized by exercise training, supplemental fish oil, an emphasis on fiber-rich, low-glycemic-index whole foods, and the "spontaneous" weight loss often seen with ad libitum consumption of such diets -- measures which are highly recommendable whether or not triglycerides are a concern.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe St., San Diego, CA 92109, USA.
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33
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Benítez S, Sánchez-Quesada JL, Ribas V, Jorba O, Blanco-Vaca F, González-Sastre F, Ordóñez-Llanos J. Platelet-activating factor acetylhydrolase is mainly associated with electronegative low-density lipoprotein subfraction. Circulation 2003; 108:92-6. [PMID: 12821559 DOI: 10.1161/01.cir.0000072791.40232.8f] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Electronegative LDL [LDL(-)], a modified subfraction of LDL present in plasma, induces the release of interleukin-8 and monocyte chemotactic protein-1 from cultured endothelial cells. METHODS AND RESULTS We demonstrate that platelet-activating factor acetylhydrolase (PAF-AH) is mainly associated with LDL(-). LDL(-) had 5-fold higher PAF-AH activity than the nonelectronegative LDL subfraction [LDL(+)] in both normolipemic and familial hypercholesterolemic subjects. Western blot analysis after SDS-PAGE confirmed these results, because a single band of 44 kDa corresponding to PAF-AH appeared in LDL(-) but not in LDL(+). Nondenaturing polyacrylamide gradient gel electrophoresis demonstrated that PAF-AH was bound to LDL(-) regardless of LDL size. In accordance with the above findings, nonesterified fatty acids, a cleavage product of PAF-AH, were increased in LDL(-) compared with LDL(+). CONCLUSIONS The high PAF-AH activity observed in LDL(-) could be related to the proinflammatory activity of these lipoproteins toward cultured endothelial cells.
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Affiliation(s)
- Sonia Benítez
- Servei de Bioquímica and Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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34
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Abstract
Several new PLA(2)s have been identified based on their nucleotide gene sequences. They were classified mainly into three groups: cytosolic PLA(2) (cPLA(2)), secretary PLA(2) (sPLA(2)), and intracellular PLA(2) (iPLA(2)). They differ from each other in terms of substrate specificity, Ca(2+) requirement and lipid modification. The questions that still remain to be addressed are the subcellular localization and differential regulation of the isoforms in various cell types and under different physiological conditions. It is required to identify the downstream events that occur upon PLA(2) activation, particularly target protein or metabolic pathway for liberated arachidonic acid or other fatty acids. Understanding the same will greatly help in the development of potent and specific pharmacological modulators that can be used for basic research and clinical applications. The information of the human and other genomes of PLA(2)s, combined with the use of proteomics and genetically manipulated mouse models of different diseases, will illuminate us about the specific and potentially overlapping roles of individual phospholipases as mediators of physiological and pathological processes. Hopefully, such understanding will enable the development of specific agents aimed at decreasing the potential contribution of individual secretary phospholipases to vascular diseases. The signaling cascades involved in the activation of cPLA(2) by mitogen activated protein kinases (MAPKs) is now evident. It has been demonstrated that p44 MAPK phosphorylates cPLA(2) and increases its activity in cells and tissues. The phosphorylation of cPLA(2) at ser505 occurs before the increase in intracellular Ca(2+) that facilitate the binding of the lipid binding domain of cPLA(2) to phospholipids, promoting its translocation to cellular membranes and AA release. Recently, a negative feed back loop for cPLA(2) activation by MAPK has been proposed. If PLA(2) activation in a given model depends on PKC, PKA, cAMP, or MAPK then inhibition of these phosphorylating enzymes may alter activities of PLA(2) isoforms during cellular injury. Understanding the signaling pathways involved in the activation/deactivation of PLA(2) during cellular injury will point to key events that can be used to prevent the cellular injury. Furthermore, to date, there is limited information available regarding the regulation of iPLA(2) or sPLA(2) by these pathways.
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Affiliation(s)
- Sajal Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal, India.
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35
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Abstract
Cardiovascular disease is the leading cause of death in most industrialized countries. However, the diagnosis and management of coronary heart disease is far from optimal. Lipoprotein-associated phospholipase A2 (Lp-PLA2), also known as platelet-activating factor acetylhydrolase, is an enzyme that hydrolyses oxidized phospholipids and is primarily associated with low-density lipoprotein. Discussed in this review is the accumulating evidence supporting the view that Lp-PLA2 is a potential biomarker of coronary heart disease and plays and an important proinflammatory role in the progression of atherosclerosis. A new ELISA method for the quantitative measurement of Lp-PLA2 mass in human plasma developed by diaDexus, Inc. is presented. Furthermore, potential clinical applications of Lp-PLA2 mass measurements are proposed.
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Affiliation(s)
- Nisha Dada
- Dia Dexus, Inc, 343 Oyster Point Boulevard, South San Francisco, Ca. 94080-1913, USA.
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36
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Abstract
Secretory phospholipase A(2) (PLA(2)) can be proatherogenic both in the circulation and in the arterial wall. In blood plasma, PLA(2) can modify the circulating lipoproteins and so induce formation of small dense LDL particles, which are associated with increased risk for cardiovascular disease. In the arterial wall, PLA(2) can hydrolyze lipoproteins. The PLA(2)-modified lipoproteins bind tightly to extracellular proteoglycans, which may lead to their enhanced retention in the arterial wall. The modified lipoproteins may also aggregate and fuse, which can lead to accumulation of their lipids within the extracellular matrix. The PLA(2)-modified particles are more susceptible to further modifications by other enzymes and agents and can be taken up by macrophages, leading to accumulation of intracellular lipids. In addition, lysophospholipids and free fatty acids, the hydrolysis products of PLA(2), promote atherogenesis. Thus, these lipid mediators can be carried, either by the PLA(2)-modified lipoproteins themselves or by albumin, into the arterial cells, which then undergo functional alterations. This may, in turn, lead to specific changes in the extracellular matrix, which increase the retention and accumulation of lipoproteins within the matrix. In the present article, we discuss the possible actions of PLA(2) enzymes, especially PLA(2)-IIA, in the arterial wall during atherogenesis.
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Affiliation(s)
- E Hurt-Camejo
- AstraZeneca R&D, Cell Biology and Biochemistry, Mölndal, Sweden.
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