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Upton JEM, Grunebaum E, Sussman G, Vadas P. Platelet Activating Factor (PAF): A Mediator of Inflammation. Biofactors 2022; 48:1189-1202. [PMID: 36029481 DOI: 10.1002/biof.1883] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022]
Abstract
Platelet-activating factor (PAF) is a phospholipid-derived mediator with an established role in multiple inflammatory states. PAF is synthesized and secreted by multiple cell types and is then rapidly hydrolyzed and degraded to an inactive metabolite, lyso-PAF, by the enzyme PAF acetylhydrolase. In addition to its role in platelet aggregation and activation, PAF contributes to allergic and nonallergic inflammatory diseases such as anaphylaxis, sepsis, cardiovascular disease, neurological disease, and malignancy as demonstrated in multiple animal models and, increasingly, in human disease states. Recent research has demonstrated the importance of the PAF pathway in multiple conditions including the prediction of severe pediatric anaphylaxis, effects on blood-brain barrier permeability, effects on reproduction, ocular diseases, and further understanding of its role in cardiovascular risk. Investigation of PAF as both a biomarker and a therapeutic target continues because of the need for directed management of inflammation. Collectively, studies have shown that therapies focused on the PAF pathway have the potential to provide targeted and effective treatments for multiple inflammatory conditions.
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Affiliation(s)
- Julia E M Upton
- Division of Immunology and Allergy, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Eyal Grunebaum
- Division of Immunology and Allergy, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Gordon Sussman
- Division of Clinical Immunology and Allergy, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Peter Vadas
- Division of Clinical Immunology and Allergy, Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
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Association Lp-PLA2 Gene Polymorphisms with Coronary Heart Disease. DISEASE MARKERS 2022; 2022:9775699. [PMID: 35818585 PMCID: PMC9271005 DOI: 10.1155/2022/9775699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/10/2022] [Indexed: 11/28/2022]
Abstract
Objectives The study evaluated the association between lipoprotein-associated phospholipase A2 (Lp-PLA2) gene polymorphisms and coronary heart disease (CHD), in order to explore the molecular genetics of CHD. Methods Groups of CHD patients (n = 283) and healthy controls (n = 261) were involved in this study. R92H, V279F, and A379V polymorphisms of LP-PLA2 gene were confirmed using polymerase chain reaction (PCR) and direct DNA sequencing. These polymorphisms and their interaction were also analyzed as potential risk factors of CHD. Results In this study population, the genotypes of R92H (GG, GA, and AA), V279F (CC, AC, and AA) and A379V (GG, GA, and AA) were studied. There was a significantly difference in frequencies of R92H between CHD patients and controls (P < 0.05). In contrast, no significant difference in frequencies of V279F and A379V existed between CHD patients and controls. Furthermore, R92H and A379V were in strong linkage disequilibrium. Conclusions These results suggested that R92H polymorphism might contribute to increased risk of CHD.
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Wu X, Lin J, Xue N, Teng J, Wang Y, Li Y, Xu X, Shen Z, Ding X, Fang Y. Relationship Between Gene Polymorphism of Methylenetetrahydrofolate Reductase C677T and Left Ventricular Hypertrophy in Chinese Patients with Chronic Kidney Disease. Lab Med 2021; 52:519-527. [PMID: 33693817 DOI: 10.1093/labmed/lmab004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the relationship between the gene polymorphism of methylenetetrahydrofolate reductase (MTHFR) C677T and left ventricular hypertrophy (LVH) in patients with chronic kidney disease (CKD). METHODS A total of 763 Chinese patients with CKD undergoing genetic testing were included in the study. The association between the gene polymorphism of MTHFR C677T and echocardiographic parameters was analyzed through univariate and multivariate analyses. RESULTS We found a remarkably positive association between MTHFR C677T gene polymorphism and LVH indexes, including interventricular septal thickness (F = 3.8; P = .022), left ventricular posterior wall thickness (F = 3.0; P = .052), left ventricular mass (F = 3.9; P = .022), and left ventricular mass index (F = 2.6; P = .075). After adjusting for the potential confounders linking the polymorphism,we found that the positive association between the polymorphism and LVH indexes still existed in patients with CKD in some multiple linear regression models (P <.05). CONCLUSION MTHFR C677T gene polymorphism may be a genetic susceptibility marker for the development of LVH in patients with CKD.
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Affiliation(s)
- Xie Wu
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jing Lin
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ning Xue
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jie Teng
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yaqiong Wang
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yang Li
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xunhui Xu
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Ziyan Shen
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xiaoqiang Ding
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yi Fang
- Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Kidney and Blood Purification, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Medical Center of Kidney Disease, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Kidney and Dialysis, Zhongshan Hospital, Fudan University, Shanghai, China
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Kono N, Arai H. Platelet-activating factor acetylhydrolases: An overview and update. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:922-931. [PMID: 30055287 DOI: 10.1016/j.bbalip.2018.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 01/22/2023]
Abstract
Platelet-activating factor acetylhydrolases (PAF-AHs) are unique members of the phospholipase A2 family that can hydrolyze the acetyl group of PAF, a signaling phospholipid that has roles in diverse (patho)physiological processes. Three types of PAF-AH have been identified in mammals, one plasma type and two intracellular types [PAF-AH (I) and PAF-AH (II)]. Plasma PAF-AH and PAF-AH (II) are monomeric enzymes that are structurally similar, while PAF-AH (I) is a multimeric enzyme with no homology to other PAF-AHs. PAF-AH (I) shows a strong preference for an acetyl group, whereas plasma PAF-AH and PAF-AH (II) also hydrolyze phospholipids with oxidatively modified fatty acids. Plasma PAF-AH has been implicated in several diseases including cardiovascular disease. PAF-AH (I) is required for spermatogenesis and is increasingly recognized as an oncogenic factor. PAF-AH (II) was recently shown to act as a bioactive lipid-producing enzyme in mast cells and thus could be a drug target for allergic diseases. This article is part of a Special Issue entitled Novel functions of phospholipase A2 Guest Editors: Makoto Murakami and Gerard Lambeau.
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Affiliation(s)
- Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; PRIME, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyodaku, Tokyo 100-0004, Japan.
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyodaku, Tokyo 100-0004, Japan
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5
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Widodo, Ramadhani AN, Nofitasari A, Puspitarini S, Priyandoko D, Saifur Rohman M, Lukitasari M. The V279F polymorphism might change protein character and immunogenicity in Lp-PLA2 protein. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2018. [DOI: 10.1016/j.ejmhg.2017.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Millwood IY, Bennett DA, Walters RG, Clarke R, Waterworth D, Johnson T, Chen Y, Yang L, Guo Y, Bian Z, Hacker A, Yeo A, Parish S, Hill MR, Chissoe S, Peto R, Cardon L, Collins R, Li L, Chen Z. A phenome-wide association study of a lipoprotein-associated phospholipase A2 loss-of-function variant in 90 000 Chinese adults. Int J Epidemiol 2016; 45:1588-1599. [PMID: 27301456 PMCID: PMC5100610 DOI: 10.1093/ije/dyw087] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2016] [Indexed: 12/20/2022] Open
Abstract
Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) has been implicated in development of atherosclerosis; however, recent randomized trials of Lp-PLA2 inhibition reported no beneficial effects on vascular diseases. In East Asians, a loss-of-function variant in the PLA2G7 gene can be used to assess the effects of genetically determined lower Lp-PLA2. Methods:PLA2G7 V279F (rs76863441) was genotyped in 91 428 individuals randomly selected from the China Kadoorie Biobank of 0.5 M participants recruited in 2004–08 from 10 regions of China, with 7 years’ follow-up. Linear regression was used to assess effects of V279F on baseline traits. Logistic regression was conducted for a range of vascular and non-vascular diseases, including 41 ICD-10 coded disease categories. Results:PLA2G7 V279F frequency was 5% overall (range 3–7% by region), and 9691 (11%) participants had at least one loss-of-function variant. V279F was not associated with baseline blood pressure, adiposity, blood glucose or lung function. V279F was not associated with major vascular events [7141 events; odds ratio (OR) = 0.98 per F variant, 95% confidence interval (CI) 0.90-1.06] or other vascular outcomes, including major coronary events (922 events; 0.96, 0.79-1.18) and stroke (5967 events; 1.00, 0.92-1.09). Individuals with V279F had lower risks of diabetes (7031 events; 0.91, 0.84-0.98) and asthma (182 events; 0.53, 0.28-0.98), but there was no association after adjustment for multiple testing. Conclusions: Lifelong lower Lp-PLA2 activity was not associated with major risks of vascular or non-vascular diseases in Chinese adults. Using functional genetic variants in large-scale prospective studies with linkage to a range of health outcomes is a valuable approach to inform drug development and repositioning.
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Affiliation(s)
- Iona Y Millwood
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Derrick A Bennett
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Robin G Walters
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Robert Clarke
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Dawn Waterworth
- GlaxoSmithKline (GSK) Medicines Research Centre, GSK, Stevenage, UK, Research Triangle Park, NC, USA and King of Prussia, PA, USA
| | - Toby Johnson
- GlaxoSmithKline (GSK) Medicines Research Centre, GSK, Stevenage, UK, Research Triangle Park, NC, USA and King of Prussia, PA, USA
| | - Yiping Chen
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Ling Yang
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Yu Guo
- Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China and
| | - Zheng Bian
- Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China and
| | - Alex Hacker
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Astrid Yeo
- GlaxoSmithKline (GSK) Medicines Research Centre, GSK, Stevenage, UK, Research Triangle Park, NC, USA and King of Prussia, PA, USA
| | - Sarah Parish
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Michael R Hill
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Stephanie Chissoe
- GlaxoSmithKline (GSK) Medicines Research Centre, GSK, Stevenage, UK, Research Triangle Park, NC, USA and King of Prussia, PA, USA
| | - Richard Peto
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Lon Cardon
- GlaxoSmithKline (GSK) Medicines Research Centre, GSK, Stevenage, UK, Research Triangle Park, NC, USA and King of Prussia, PA, USA
| | - Rory Collins
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
| | - Liming Li
- Chinese Academy of Medical Sciences, Dong Cheng District, Beijing, China and.,Department of Epidemiology & Biostatistics, Peking University Health Science Centre, Beijing, China
| | - Zhengming Chen
- Clinical Trial Service Unit & Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, UK
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Karasawa K. Naturally Occurring Missense Mutation in Plasma PAF-AH Among the Japanese Population. Enzymes 2015; 38:117-43. [PMID: 26612650 DOI: 10.1016/bs.enz.2015.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A single nucleotide polymorphism in the plasma PAF-AH enzyme, i.e., G994T, which causes the substitution of Val at amino acid 279 with Phe (V279F), has been found in the Japanese population. This enzyme preferentially degrades oxidatively modulated or truncated phospholipids; therefore, it has been suggested that this enzyme may prevent the accumulation of proinflammatory and proatherogenic oxidized phospholipids. This hypothesis is supported by the higher prevalence of the V279F mutation in patients with asthmatic and atherosclerotic diseases, as compared with healthy controls. This mutation is rare in the Caucasian population. The plasma PAF-AH mass and enzyme activity are distributed over a wide range in the plasma and they are positively correlated with low-density lipoprotein (LDL) cholesterol. However, several clinical studies in the Caucasian population have suggested that this enzyme has the opposite role. This enzyme plays an active role in the development and progression of atherosclerosis via proinflammatory and proatherogenic lysophosphatidylcholine and oxidized fatty acids produced through the oxidation of LDL by this enzyme. Thus, plasma PAF-AH is a unique enzyme with dual roles in human inflammatory diseases. In this chapter, on the basis of recent findings we describe the association between a naturally occurring missense mutation in plasma PAF-AH and human diseases especially including atherosclerosis and asthma.
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Affiliation(s)
- Ken Karasawa
- Faculty of Pharmaceutical Sciences, Teikyo University, Tokyo, Japan.
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Hoogeveen RC, Ballantyne CM. PLAC™ test for identification of individuals at increased risk for coronary heart disease. Expert Rev Mol Diagn 2014; 5:9-14. [PMID: 15723587 DOI: 10.1586/14737159.5.1.9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent advances in cardiovascular research point to a critical role of inflammatory processes in the etiology of cardiovascular disease. This has led to the discovery of novel inflammatory biomarkers, which may be useful as additional screening tools for the identification of individuals at increased risk of coronary heart disease. One such novel inflammatory biomarker is lipoprotein-associated phospholipase A(2). This review discusses the recent development of a US Food and Drug Administration-approved blood test for lipoprotein-associated phospholipase A(2) (PLAC test, diaDexus, Inc.) and its efficacy as a predictive biomarker of risk for cardiovascular disease. More specifically, the article addresses the potential target group most likely to benefit from this new screening test and provides a prospective scenario for its implementation.
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Affiliation(s)
- Ron C Hoogeveen
- Baylor College of Medicine, Section of Atherosclerosis & Lipoprotein Research, Department of Medicine, Center for Cardiovascular Disease Prevention, Houston, TX 77030, USA.
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Rosenson RS, Stafforini DM. Modulation of oxidative stress, inflammation, and atherosclerosis by lipoprotein-associated phospholipase A2. J Lipid Res 2012; 53:1767-82. [PMID: 22665167 DOI: 10.1194/jlr.r024190] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), also known as platelet-activating factor acetylhydrolase (PAF-AH), is a unique member of the phospholipase A(2) superfamily. This enzyme is characterized by its ability to specifically hydrolyze PAF as well as glycerophospholipids containing short, truncated, and/or oxidized fatty acyl groups at the sn-2 position of the glycerol backbone. In humans, Lp-PLA(2) circulates in active form as a complex with low- and high-density lipoproteins. Clinical studies have reported that plasma Lp-PLA(2) activity and mass are strongly associated with atherogenic lipids and vascular risk. These observations led to the hypothesis that Lp-PLA(2) activity and/or mass levels could be used as biomarkers of cardiovascular disease and that inhibition of the activity could offer an attractive therapeutic strategy. Darapladib, a compound that inhibits Lp-PLA(2) activity, is anti-atherogenic in mice and other animals, and it decreases atherosclerotic plaque expansion in humans. However, disagreement continues to exist regarding the validity of Lp-PLA(2) as an independent marker of atherosclerosis and a scientifically justified target for intervention. Circulating Lp-PLA(2) mass and activity are associated with vascular risk, but the strength of the association is reduced after adjustment for basal concentrations of the lipoprotein carriers with which the enzyme associates. Genetic studies in humans harboring an inactivating mutation at this locus indicate that loss of Lp-PLA(2) function is a risk factor for inflammatory and vascular conditions in Japanese cohorts. Consistently, overexpression of Lp-PLA(2) has anti-inflammatory and anti-atherogenic properties in animal models. This thematic review critically discusses results from laboratory and animal studies, analyzes genetic evidence, reviews clinical work demonstrating associations between Lp-PLA(2) and vascular disease, and summarizes results from animal and human clinical trials in which administration of darapladib was tested as a strategy for the management of atherosclerosis.
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Jang Y, Waterworth D, Lee JE, Song K, Kim S, Kim HS, Park KW, Cho HJ, Oh IY, Park JE, Lee BS, Ku HJ, Shin DJ, Lee JH, Jee SH, Han BG, Jang HY, Cho EY, Vallance P, Whittaker J, Cardon L, Mooser V. Carriage of the V279F null allele within the gene encoding Lp-PLA₂ is protective from coronary artery disease in South Korean males. PLoS One 2011; 6:e18208. [PMID: 21490708 PMCID: PMC3071750 DOI: 10.1371/journal.pone.0018208] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 02/22/2011] [Indexed: 01/28/2023] Open
Abstract
Background The Asia-specific PLA2G7 994G-T transversion leads to V279F substitution within the lipoprotein-associated phospholipase-A2 (Lp-PLA2) and to absence of enzyme activity in plasma. This variant offers a unique natural experiment to assess the role of Lp-PLA2 in the pathogenesis of coronary artery disease (CAD) in humans. Given conflicting results from mostly small studies, a large two-stage case-control study was warranted. Methodology/Principal Findings PLA2G7 V279F genotypes were initially compared in 2890 male cases diagnosed with CAD before age 60 with 3128 male controls without CAD at age 50 and above and subsequently in a second independent male dataset of 877 CAD cases and 1230 controls. In the first dataset, the prevalence of the 279F null allele was 11.5% in cases and 12.8% in controls. After adjustment for age, body mass index, diabetes, smoking, glucose and lipid levels, the OR (95% CI) for CAD for this allele was 0.80 (0.66–0.97, p = 0.02). The results were very similar in the second dataset, despite lower power, with an allele frequency of 11.2% in cases and 12.5% in controls, leading to a combined OR of 0.80 (0.69–0.92), p = 0.002. The magnitude and direction of this genetic effect were fully consistent with large epidemiological studies on plasma Lp-PLA2 activity and CAD risk. Conclusions Natural deficiency in Lp-PLA2 activity due to carriage of PLA2G7 279F allele protects from CAD in Korean men. These results provide evidence for a causal relationship between Lp-PLA2 and CAD, and support pharmacological inhibition of this enzyme as an innovative way to prevent CAD.
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Affiliation(s)
- Yangsoo Jang
- Division of Cardiology, Cardiovascular Genome Center, Yonsei University College of Medicine, Yonsei, South Korea
| | - Dawn Waterworth
- Genetics Division, Medicine Discovery and Development, Research and Development, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
- * E-mail:
| | | | - Kijoung Song
- Genetics Division, Medicine Discovery and Development, Research and Development, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
| | | | - Hyo-Soo Kim
- Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea
| | - Kyung Woo Park
- Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea
| | - Hyun-Jai Cho
- Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea
| | - Il-Young Oh
- Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, South Korea
| | - Jeong Euy Park
- Division of Cardiovascular Disease, Samsung Medical Center, Sung Kyun Kwan University, Seoul, South Korea
| | - Bok-Soo Lee
- Division of Cardiovascular Disease, Samsung Medical Center, Sung Kyun Kwan University, Seoul, South Korea
| | - Hyo Jeong Ku
- Division of Cardiovascular Disease, Samsung Medical Center, Sung Kyun Kwan University, Seoul, South Korea
| | - Dong-Jik Shin
- Division of Cardiology, Cardiovascular Genome Center, Yonsei University College of Medicine, Yonsei, South Korea
| | - Jong Ho Lee
- Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, South Korea
| | - Sun Ha Jee
- Department of Epidemiology and Health Promotion, Institute for Health Promotion, Graduate School of Public Health, Yonsei University, Seoul, South Korea
| | - Bok-Ghee Han
- Center for Genome Science, National Institute of Health, Seoul, South Korea
| | | | | | - Patrick Vallance
- Medicine Discovery and Development, Research and Development, GlaxoSmithKline Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
| | - John Whittaker
- Genetics Division, Medicine Discovery and Development, Research and Development, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
| | - Lon Cardon
- Genetics Division, Medicine Discovery and Development, Research and Development, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
| | - Vincent Mooser
- Genetics Division, Medicine Discovery and Development, Research and Development, GlaxoSmithKline, Philadelphia, Pennsylvania, United States of America and Greenford, United Kingdom
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Fan P, Liu HW, Wang XS, Zhang F, Song Q, Li Q, Wu HM, Bai H. Identification of the G994T polymorphism in exon 9 of plasma platelet-activating factor acetylhydrolase gene as a risk factor for polycystic ovary syndrome. Hum Reprod 2010; 25:1288-94. [PMID: 20185515 DOI: 10.1093/humrep/deq047] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Low-grade chronic inflammation and greater risks of cardiovascular diseases are often present in patients with polycystic ovary syndrome (PCOS). Platelet-activating factor (PAF) acetylhydrolase (PAF-AH) hydrolyzes and inactivates PAF and PAF-like oxidized phospholipids that are potent lipid mediators involved in inflammation and atherosclerosis. Deficiency of this enzyme is caused by a missense mutation (G994 --> T) in exon 9 of the plasma PAF-AH gene. The aim of the study was to investigate a possible association of this polymorphism with the risk of PCOS and to evaluate the effects of the genotype on the activity and distribution of PAFAH in Chinese patients. METHODS A total of 661 subjects (346 patients with PCOS and 315 healthy control women) from a population of Chinese Han nationality in Chengdu area were included in this study. PAFAH G994T genotype was studied using PCR and restriction fragment length polymorphism analysis. Total plasma PAF-AH, high-density lipoprotein (HDL)-associated PAF-AH (H-PAF-AH) and low-density lipoprotein (LDL)-associated PAF-AH (L-PAF-AH) activities were measured by the trichloroacetic acid precipitation procedure using [(3)H-acetyl] PAF and PAF C-16 as a substrate. RESULTS The prevalence of the mutant genotype (GT + TT) was significantly more frequent in patients with PCOS than in control subjects (12.7 versus 6.0%, P = 0.003). Genotype (GT + TT) remained a significant predictor for PCOS (P = 0.020) in prognostic models including age, body mass index, insulin resistance index, triglyceride, HDL and LDL as covariates. There was a significant difference in plasma PAF-AH, L-PAF-AH and H-PAF-AH activities between GG and GT genotypes in both the patient and control groups. The ratio of L-PAF-AH to H-PAF-AH activities was significantly higher after adjustment for multiple variables in patients with GT genotype compared with patients with GG genotype (P = 0.003). There were no significant differences in clinical, biochemical and metabolic parameters according to PAFAH G994T genotyping in patients with PCOS and control women. CONCLUSIONS The G994T polymorphism in PAFAH gene may be one of the genetic determinants for PCOS in Chinese Han women.
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Affiliation(s)
- Ping Fan
- Laboratory of Genetic Disease and Perinatal Medicine, West China Second University Hospital, Sichuan University, Chengdu 610041, Sichuan, People's Republic of China
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Functional Consequences of Mutations and Polymorphisms in the Coding Region of the PAF Acetylhydrolase (PAF-AH) Gene. Pharmaceuticals (Basel) 2009; 2:94-117. [PMID: 27713227 PMCID: PMC3978535 DOI: 10.3390/ph2030094] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 11/10/2009] [Accepted: 11/19/2009] [Indexed: 12/03/2022] Open
Abstract
In the past several years a number of alterations in the PAF-AH/PLA2G7/LpPLA2 gene have been described. These include inactivating mutations, polymorphisms in the coding region, and other genetic changes located in promoter and intronic regions of the gene. The consequences associated with these genetic variations have been evaluated from different perspectives, including in vitro biochemical and molecular studies and clinical analyses in human subjects. This review highlights the current state of the field and suggests new approaches that can be used to evaluate functional consequences associated with mutations and polymorphisms in the PAF-AH gene.
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Stafforini DM. Biology of platelet-activating factor acetylhydrolase (PAF-AH, lipoprotein associated phospholipase A2). Cardiovasc Drugs Ther 2008; 23:73-83. [PMID: 18949548 DOI: 10.1007/s10557-008-6133-8] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 08/06/2008] [Indexed: 12/26/2022]
Abstract
INTRODUCTION This article is focused on platelet-activating factor acetylhydrolase (PAF-AH), a lipoprotein bound, calcium-independent phospholipase A(2) activity also referred to as lipoprotein-associated phospholipase A(2) or PLA(2)G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress. DISCUSSION Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. This mechanism is likely responsible for the observed up-regulation of PAF-AH during atherosclerosis and suggests that increased expression of this enzyme is a physiological response to inflammatory stimuli. Administration of recombinant forms of PAF-AH attenuate inflammation in a variety of experimental models. Conversely, genetic deficiency of PAF-AH in defined human populations increases the severity of atherosclerosis and other syndromes. Recent advances pointing to an interplay among oxidized phospholipid substrates, Lp(a), and PAF-AH could hold the key to a number of unanswered questions.
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Affiliation(s)
- Diana M Stafforini
- Huntsman Cancer Institute and Department of Internal Medicine, University of Utah, 2000 Circle of Hope, Suite 3364, Salt Lake City, UT 84112-5550, USA.
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14
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Sutton BS, Crosslin DR, Shah SH, Nelson SC, Bassil A, Hale AB, Haynes C, Goldschmidt-Clermont PJ, Vance JM, Seo D, Kraus WE, Gregory SG, Hauser ER. Comprehensive genetic analysis of the platelet activating factor acetylhydrolase (PLA2G7) gene and cardiovascular disease in case-control and family datasets. Hum Mol Genet 2008; 17:1318-28. [PMID: 18204052 DOI: 10.1093/hmg/ddn020] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Platelet-activating factor acetylhydrolase (PLA2G7) is a potent pro- and anti-inflammatory molecule that has been implicated in multiple inflammatory disease processes, including cardiovascular disease. The goal of this study was to investigate the genetic effects of PLA2G7 on coronary artery disease (CAD) risk in two large, independent datasets with CAD. Using a haplotype tagging (ht) approach, 19 ht single nucleotide polymorphisms (SNPs) were genotyped in CATHGEN case-control samples (cases = 806 and controls = 267) and in the GENECARD Family Study (n = 1101 families, 2954 individuals). Single SNP analysis using logistic regression revealed nine SNPs with significant association in all CATHGEN subjects (P = 0.0004-0.02). CATHGEN cases were further stratified into subgroups based on age of CAD onset (AOO) and severity of disease; 599 young affecteds (YA, AOO <56) and 207 old affected (OA, AOO >56). Significant genetic effects were observed in both OA and YA (P = 0.0001-0.02). The GENECARD probands demonstrated results similar to those seen in the YA CATHGEN cases (P = 0.002-0.05). Of the 19 SNPs genotyped, 3 SNPs result in nonsynonymous coding changes (I198T, A379V and R92H). Two of the coding SNPs, R92H and A379V, constitute two of the most significantly associated SNPs, even after Bonferroni correction and appear to represent independent associations (r(2) = 0.09). Multiple additional polymorphisms in low linkage disequilibrium with these coding SNPs were also strongly associated. In summary, PLA2G7 represents an important, potentially functional candidate in the pathophysiology of CAD based on replicated associations using two independent datasets and multiple statistical approaches. Further functional studies involving a combination of risk alleles are warranted.
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Affiliation(s)
- Beth S Sutton
- Center for Human Genetics, Duke University Medical Center, Durham, NC 27710, USA
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Gora S, Lambeau G, Bollinger JG, Gelb M, Ninio E, Karabina SA. The proinflammatory mediator Platelet Activating Factor is an effective substrate for human group X secreted phospholipase A2. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1093-9. [PMID: 16962371 DOI: 10.1016/j.bbalip.2006.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 06/19/2006] [Accepted: 08/02/2006] [Indexed: 11/29/2022]
Abstract
Platelet Activating Factor (PAF) is a potent mediator of inflammation whose biological activity depends on the acetyl group esterified at the sn-2 position of the molecule. PAF-acetylhydrolase (PAF-AH), a secreted calcium-independent phospholipase A(2), is known to inactivate PAF by formation of lyso-PAF and acetate. However, PAF-AH deficient patients are not susceptible to the biological effects of inhaled PAF in airway inflammation, suggesting that other enzymes may regulate extracellular levels of PAF. We therefore examined the hydrolytic activity of the recently described human group X secreted phospholipase A(2) (hGX sPLA(2)) towards PAF. Among different sPLA(2)s, hGX sPLA(2) has the highest affinity towards phosphatidylcholine (PC), the major phospholipid of cellular membranes and plasma lipoproteins. Our results show that unlike group IIA, group V, and the pancreatic group IB sPLA(2), recombinant hGX sPLA(2) can efficiently hydrolyze PAF. The hydrolysis of PAF by hGX sPLA(2) rises abruptly when the concentration of PAF passes through its critical micelle concentration suggesting that the enzyme undergoes interfacial binding and activation to PAF. In conclusion, our study shows that hGX sPLA(2) may be a novel player in PAF regulation during inflammatory processes.
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Affiliation(s)
- Sarah Gora
- INSERM U525, Université Pierre et Marie Curie-Paris 6, Faculté de Médecine Pierre et Marie Curie, Paris, France
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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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Unno N, Sakaguchi T, Nakamura T, Yamamoto N, Sugatani J, Miwa M, Konno H. A single nucleotide polymorphism in the plasma PAF acetylhydrolase gene and risk of atherosclerosis in Japanese patients with peripheral artery occlusive disease. J Surg Res 2006; 134:36-43. [PMID: 16650870 DOI: 10.1016/j.jss.2006.02.058] [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] [Received: 01/09/2006] [Revised: 02/20/2006] [Accepted: 02/27/2006] [Indexed: 11/20/2022]
Abstract
BACKGROUND Plasma PAF-acetylhydrolase (PAF-AH) gene polymorphisms (G994 --> T in exon 9) and the resulting deficiency of enzyme activity were identified in the Japanese population. The objective of this study was to assess the joint effect of the polymorphism and hypercholesterolemia on risk of atherosclerosis. METHODS AND RESULTS We performed a case-control study including 150 patients who underwent operation for peripheral arterial occlusive disease (PAOD) and 158 controls matched for age and sex. Genomic DNA was analyzed for the mutant allele by a specific polymerase-chain reaction. Plasma PAF-AH activity was measured in both groups. The patients with multiple atherosclerotic diseases showed higher levels of PAF-AH activities than the patients with only peripheral artery occlusive disease among normal genotypes. PAOD patients were assessed either with or without polymorphism or hypercholesterolemia in regard to accompanying coronary artery disease or stroke. The prevalence of the polymorphism was significantly more frequent in the patients with PAOD. The plasma PAF-AH activity was correlated with total cholesterol and LDL level, and inversely related with HDL in normal genotype (GG) PAOD patients. However, neither the correlation nor the inverse relation was found in patients with the polymorphism. Patients with both hypercholesterolemia and the polymorphisms revealed a relative risk for other atherosclerotic disease of 11.5 (6.0-40.3) compared with normal genotype and normal lipid level. CONCLUSION The plasma PAF-AH gene polymorphism and hypercholesterolemia may interact and increase the risk of atherosclerosis.
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Affiliation(s)
- Naoki Unno
- Second Department of Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.
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Castro Faria Neto HC, Stafforini DM, Prescott SM, Zimmerman GA. Regulating inflammation through the anti-inflammatory enzyme platelet-activating factor-acetylhydrolase. Mem Inst Oswaldo Cruz 2005; 100 Suppl 1:83-91. [PMID: 15962103 DOI: 10.1590/s0074-02762005000900014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Platelet-activating factor (PAF) is one of the most potent lipid mediators involved in inflammatory events. The acetyl group at the sn-2 position of its glycerol backbone is essential for its biological activity. Deacetylation induces the formation of the inactive metabolite lyso-PAF. This deacetylation reaction is catalyzed by PAF-acetylhydrolase (PAF-AH), a calcium independent phospholipase A2 that also degrades a family of PAF-like oxidized phospholipids with short sn-2 residues. Biochemical and enzymological evaluations revealed that at least three types of PAF-AH exist in mammals, namely the intracellular types I and II and a plasma type. Many observations indicate that plasma PAF AH terminates signals by PAF and oxidized PAF-like lipids and thereby regulates inflammatory responses. In this review, we will focus on the potential of PAF-AH as a modulator of diseases of dysregulated inflammation.
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Affiliation(s)
- Hugo C Castro Faria Neto
- Laboratório de Imunofarmacologia, Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, RJ, Brasil
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Stafforini DM, McIntyre TM, Zimmerman GA, Prescott SM. Platelet-activating factor, a pleiotrophic mediator of physiological and pathological processes. Crit Rev Clin Lab Sci 2004; 40:643-72. [PMID: 14708958 DOI: 10.1080/714037693] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Platelet-activating factor (PAF) is a potent proinflammatory phospholipid with diverse pathological and physiological effects. This bioactive phospholipid mediates processes as diverse as wound healing, physiological inflammation, apoptosis, angiogenesis, reproduction and long-term potentiation. Recent progress has demonstrated the participation of MAP kinase signaling pathways as modulators of the two critical enzymes, phospholipase A2 and acetyltransferase, involved in the remodeling pathway of PAF biosynthesis. The unregulated production of structural analogs of PAF by non-specific oxidative reactions has expanded this superfamily of signaling molecules to include "PAF-like" lipids whose mode of action is identical to that of authentic PAF. The action of members of this family is mediated by the PAF receptor, a G protein-coupled membrane-spanning molecule that can engage multiple signaling pathways in various cell types. Inappropriate activation of this signaling pathway is associated with many diseases in which inflammation is thought to be one of the underlying features. Inactivation of all members of the PAF superfamily occurs by a unique class of enzymes, the PAF acetylhydrolases, that have been characterized at the molecular level and that terminate signals initiated by both regulated and unregulated PAF production.
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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
PURPOSE OF REVIEW Although findings obtained from various studies are inconclusive in determining whether plasma platelet-activating factor acetylhydrolase, or lipoprotein-associated phospholipase A2, plays a proatherogenic or antiatherogenic role in atherosclerosis, many recent reviews appear to favor it as a risk factor for coronary artery disease. To provide a contrasting view, this review focuses on the enzyme's antiatherogenic and antiinflammatory properties. RECENT FINDINGS A recent report demonstrates that plasma platelet-activating factor acetylhydrolase activity increases in men and women with stable angina or acute coronary syndromes, supporting previously published data that plasma levels of the protein are independently and positively associated with the risk of coronary artery disease. In contrast, at least four lines of evidence indicate that the enzyme has strong antiatherogenic properties: (1) it inhibits the effects of LDL oxidation, (2) genetic deficiency of plasma levels constitutes a risk factor for vascular diseases including atherosclerosis, (3) adenoviral transfer of the protein reduces atherosclerosis in apolipoprotein E-deficient mice, and (4) pretreatment of an electronegative LDL subfraction isolated from hypercholesterolemic human plasma with a recombinant platelet-activating factor acetylhydrolase completely abolishes the proapoptotic effects of the electronegative LDL on vascular endothelial cells. Additionally, treatment with the recombinant product reduced mortality from severe sepsis in a phase IIb clinical trial. In an animal study, transfection of tumor cells with platelet-activating factor acetylhydrolase inhibited tumor growth at the site of implantation. SUMMARY Plasma platelet-activating factor acetylhydrolase becomes progressively activated as atherosclerosis progresses, but lines of evidence indicate that the enzyme possesses potent antiatherogenic and antiinflammatory properties. This raises the question of whether increased activity is a cause or a result of atherosclerosis and, consequently, whether inhibiting the enzyme's activities may decelerate or accelerate the progress of the disease.
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Affiliation(s)
- Chu-Huang Chen
- Department of Medicine, Section of Atherosclerosis and Lipoprotein Research, Baylor College of Medicine, 6565 Fannin, Mail Station A-601, Houston, TX 77030, USA.
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Caslake MJ, Packard CJ. Lipoprotein-associated phospholipase A2 (platelet-activating factor acetylhydrolase) and cardiovascular disease. Curr Opin Lipidol 2003; 14:347-52. [PMID: 12865731 DOI: 10.1097/00041433-200308000-00002] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Plasma lipoproteins carry a number of highly active enzymes in the circulation. One of these is lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), also known as platelet-activating factor acetylhydrolase. This review addresses the molecular properties of Lp-PLA(2), the controversy surrounding its role in atherosclerosis and the regulation of its plasma levels in humans. RECENT FINDINGS Recent reports indicate that the enzyme Lp-PLA(2) found in both LDL and HDL may be independently regulated in these lipoprotein subclasses and have distinct roles in atherogenesis. Seminal findings establishing the response-to-retention hypothesis of atherosclerosis support further the potentially damaging role that in-situ release of LDL-associated oxidative products by Lp-PLA(2) may have in the formation of arterial wall lesions. In the mouse, where Lp-PLA(2) circulates mainly bound to HDL, overexpression leads to reduced atherosclerosis, raising the possibility that the enzyme in HDL may have a protective role. Further evidence for a potential protective role is seen in studies of partial or complete deficiency of the enzyme. In the more general setting of population studies, however, it is clear that Lp-PLA(2) is a positive risk factor for coronary disease and measurements of its mass may contribute to the prediction of coronary heart disease risk, especially in individuals with low LDL cholesterol levels. SUMMARY Lp-PLA(2) is an enzyme with potentially multiple risks in atherosclerosis. In humans the weight of evidence suggests that it is a positive risk factor for coronary heart disease - an observation commensurate with its position in the direct pathological sequence leading from formation of oxidized LDL in the artery wall to cellular dysfunction and formation of lesions.
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Affiliation(s)
- Muriel J Caslake
- Department of Pathological Biochemistry, Glasgow Royal Infirmary, Glasgow, UK.
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Karasawa K, Harada A, Satoh N, Inoue K, Setaka M. Plasma platelet activating factor-acetylhydrolase (PAF-AH). Prog Lipid Res 2003; 42:93-114. [PMID: 12547653 DOI: 10.1016/s0163-7827(02)00049-8] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The platelet-activating factor-acetylhydrolase (PAF-AH) is an enzyme which catalyzes the hydrolysis of acetyl ester at the sn-2 position of PAF. The family of PAF-AHs consists of two intracellular isoforms (Ib and II), and one secreted isoform (plasma). These PAF-AHs show different biochemical characteristics and molecular structures. Plasma PAF-AH and intracellular isoform, II degrade not only PAF but also oxidatively fragmented phospholipids with potent biological activities. Among these PAF-AHs, plasma PAF-AH has been the target of many clinical studies in inflammatory diseases, such as asthma, sepsis, and vascular diseases, because the plasma PAF-AH activity in the patients with these diseases is altered when compared with normal individuals. Finding a genetic deficiency in the plasma PAF-AH opened the gate in elucidating the protecting role of this enzyme in inflammatory diseases. The most common loss-of-function mutation, V279F, is found in more than 30% of Japanese subjects (4% homozygous, 27% heterozygous). This single nucleotide polymorphism in plasma PAF-AH and the resulting enzymatic deficiency is thought to be a genetic risk factor in various inflammatory diseases in Japanese subjects. Administration of recombinant plasma PAF-AH or transfer of the plasma PAF-AH gene improves pathology in animal models. Therefore, substitution of plasma PAF-AH would be an effective in the treatment of the patients with the inflammatory diseases and a novel clinical approach. In addition, the detection of polymorphisms in the plasma PAF-AH gene and abnormalities in enzyme activity would be beneficial in the diagnosis of the inflammatory diseases.
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Affiliation(s)
- Ken Karasawa
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan.
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Unno N, Nakamura T, Mitsuoka H, Saito T, Miki K, Ishimaru K, Sugatani J, Miwa M, Nakamura S. Single nucleotide polymorphism (G994-->T) in the plasma platelet-activating factor-acetylhydrolase gene is associated with graft patency of femoropopliteal bypass. Surgery 2002; 132:66-71. [PMID: 12110797 DOI: 10.1067/msy.2002.124931] [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] [Indexed: 11/22/2022]
Abstract
BACKGROUND Plasma platelet-activating factor-acetylhydrolase (PAF-AH) is known to catalyze platelet-activating factor (PAF). The single nucleotide polymorphism (SNP) of plasma PAF-AH gene (G994 -->T in exon 9) is associated with a decreased level of plasma PAF-AH activity. This study analyzed the risk of the SNP on graft occlusion of femoropopliteal bypass in patients with atherosclerotic occlusive disease. METHODS We retrospectively assessed the patency of 50 above-knee femoropopliteal bypass grafting in 50 patients. Genomic DNA was analyzed for the mutant allele. Plasma PAF-AH activity was measured by radioimmunoassay. RESULTS The 10-year cumulative primary patency of the bypass was 78.5% in GG (normal genotype) and 50.0% in GT (heterozygous) or TT (homozygous deficient) (P <.05, Kaplan-Meier method). The relative risk of graft failure in GT or TT genotypes was 1.68 (P =.08, Cox proportional hazards model). PAF-AH activity (nmol/min/50 microL) was 1.92 +/- 0.82 in patients with patent grafts and 1.42 +/- 0.47 in those with occluded grafts (mean +/- standard deviation; P <.05, unpaired t test). CONCLUSIONS The SNP of plasma PAF-AH was associated with a decreased primary graft patency of above-knee femoropopliteal bypass. The risk of graft failure may increase when patients have the SNP. To confirm the independent risk of graft failure by the SNP, further study is necessary and prospective study should be performed.
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Affiliation(s)
- Naoki Unno
- Second Department of Surgery, Hamamatsu University School of Medicine, Japan
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