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Liang L, Xie Q, Sun C, Wu Y, Zhang W, Li W. Phospholipase A2 group IIA correlates with circulating high-density lipoprotein cholesterol and modulates cholesterol efflux possibly through regulation of PPAR-γ/LXR-α/ABCA1 in macrophages. J Transl Med 2021; 19:484. [PMID: 34838043 PMCID: PMC8626914 DOI: 10.1186/s12967-021-03151-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/17/2021] [Indexed: 12/13/2022] Open
Abstract
Background Secretory phospholipase A2 group IIA (sPLA2-IIA) is an independent risk factor for cardiovascular disease, but its role on high-density lipoprotein cholesterol (HDL-C) level has not been clarified. The aim of the present study was to explore the association between circulating sPLA2-IIA and HDL-C, and to evaluate if sPLA2-IIA enhances cholesterol efflux capacity through regulation of peroxisome proliferator-activated receptor γ (PPAR-γ), liver X receptor α (LXR-α), and ATP-binding cassette A1 (ABCA1). Methods 131 patients with coronary artery disease were enrolled. The plasma level of sPLA2-IIA was tested with enzyme-linked immunosorbent assay kit, and serum lipids were assessed by biochemical analyzer. Human monocyte-macrophage cell line THP-1 was co-incubated with sPLA2-IIA in the presence/absence of selective PPAR-γ antagonist GW9662 in vitro. Real-time PCR and Western-blot were employed to measure the mRNA and protein expressions of PPAR-γ, LXR-α, and ABCA1, respectively. The cholesterol efflux was evaluated by using an assay kit. Results In subjects, circulating level of sPLA2-IIA was positively related with that of HDL-C (r = 0.196, p = 0.024). The plasma level of sPLA2-IIA was significantly higher in the high HDL-C (≥ 1.04 mmol/L) group (7477.828 pg/mL) than that in low HDL-C (< 1.04 mmol/L) group (5836.92 pg/mL, p = 0.004). For each increase of 1 pg/μl in sPLA2-IIA level, the adjusted odds ratio for HDL-C ≥ 1.04 mmol/L was 1.143. Co-incubation of THP-1 cells with sPLA2-IIA resulted in increased expressions of PPAR-γ, LXR-α, and ABCA1, as well as enhanced cholesterol efflux capacity, that were all reversed by administration of GW9662. Conclusions Circulating sPLA2-IIA was positively associated with HDL-C. PPAR-γ/LXR-α/ABCA1 might be responsible for sPLA2-IIA-regulated cholesterol efflux in macrophages. Supplementary Information The online version contains supplementary material available at 10.1186/s12967-021-03151-3.
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Affiliation(s)
- Ling Liang
- Department of Cardiology, Xiamen Key Laboratory of Cardiac Electrophysiology, Xiamen Institute of Cardiovascular Diseases, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China.,Department of Cardiology, The Third Clinical Medical College, Fujian Medical University, Fuzhou, 350122, China
| | - Qiang Xie
- Department of Cardiology, Xiamen Key Laboratory of Cardiac Electrophysiology, Xiamen Institute of Cardiovascular Diseases, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China.,Department of Cardiology, The Third Clinical Medical College, Fujian Medical University, Fuzhou, 350122, China
| | - Changqing Sun
- Department of Cardiology, Xiamen Key Laboratory of Cardiac Electrophysiology, Xiamen Institute of Cardiovascular Diseases, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China
| | - Yuanhui Wu
- Department of Rheumatology and Clinical Immunology, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China
| | - Wei Zhang
- Department of Cardiology, Xiamen Key Laboratory of Cardiac Electrophysiology, Xiamen Institute of Cardiovascular Diseases, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China.
| | - Weihua Li
- Department of Cardiology, Xiamen Key Laboratory of Cardiac Electrophysiology, Xiamen Institute of Cardiovascular Diseases, The First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361003, China. .,Department of Cardiology, The Third Clinical Medical College, Fujian Medical University, Fuzhou, 350122, China.
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Cook NL, Pjanic M, Emmerich AG, Rao AS, Hetty S, Knowles JW, Quertermous T, Castillejo-López C, Ingelsson E. CRISPR-Cas9-mediated knockout of SPRY2 in human hepatocytes leads to increased glucose uptake and lipid droplet accumulation. BMC Endocr Disord 2019; 19:115. [PMID: 31664995 PMCID: PMC6820957 DOI: 10.1186/s12902-019-0442-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The prevalence of obesity and its comorbidities, including type 2 diabetes mellitus (T2DM), is dramatically increasing throughout the world; however, the underlying aetiology is incompletely understood. Genome-wide association studies (GWAS) have identified hundreds of genec susceptibility loci for obesity and T2DM, although the causal genes and mechanisms are largely unknown. SPRY2 is a candidate gene identified in GWAS of body fat percentage and T2DM, and has recently been linked to insulin production in pancreatic β-cells. In the present study, we aimed to further understand SPRY2 via functional characterisation in HepG2 cells, an in vitro model of human hepatocytes widely used to investigate T2DM and insulin resistance. METHODS CRISPR-Cas9 genome editing was used to target SPRY2 in HepG2 cells, and the functional consequences of SPRY2 knockout (KO) and overexpression subsequently assessed using glucose uptake and lipid droplet assays, measurement of protein kinase phosphorylation and RNA sequencing. RESULTS The major functional consequence of SPRY2 KO was a significant increase in glucose uptake, along with elevated lipid droplet accumulation. These changes were attenuated, but not reversed, in cells overexpressing SPRY2. Phosphorylation of protein kinases across key signalling pathways (including Akt and mitogen activated protein kinases) was not altered after SPRY2 KO. Transcriptome profiling in SPRY2 KO and mock (control) cells revealed a number of differentially expressed genes related to cholesterol biosynthesis, cell cycle regulation and cellular signalling pathways. Phospholipase A2 group IIA (PLA2G2A) mRNA level was subsequently validated as significantly upregulated following SPRY2 KO, highlighting this as a potential mediator downstream of SPRY2. CONCLUSION These findings suggest a role for SPRY2 in glucose and lipid metabolism in hepatocytes and contribute to clarifying the function of this gene in the context of metabolic diseases.
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Affiliation(s)
- Naomi L Cook
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Milos Pjanic
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Andrew G Emmerich
- Molecular Systems Biology, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Abhiram S Rao
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Susanne Hetty
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Joshua W Knowles
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA
| | - Thomas Quertermous
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA
| | - Casimiro Castillejo-López
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Immunology, Genetics and Pathology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Erik Ingelsson
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA.
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Kuefner MS, Pham K, Redd JR, Stephenson EJ, Harvey I, Deng X, Bridges D, Boilard E, Elam MB, Park EA. Secretory phospholipase A 2 group IIA modulates insulin sensitivity and metabolism. J Lipid Res 2017; 58:1822-1833. [PMID: 28663239 DOI: 10.1194/jlr.m076141] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/08/2017] [Indexed: 12/22/2022] Open
Abstract
Secretory phospholipase A2 group IIA (PLA2G2A) is a member of a family of secretory phospholipases that have been implicated in inflammation, atherogenesis, and antibacterial actions. Here, we evaluated the role of PLA2G2A in the metabolic response to a high fat diet. C57BL/6 (BL/6) mice do not express PLA2g2a due to a frameshift mutation. We fed BL/6 mice expressing the human PLA2G2A gene (IIA+ mice) a fat diet and assessed the physiologic response. After 10 weeks on the high fat diet, the BL/6 mice were obese, but the IIA+ mice did not gain weight or accumulate lipid. The lean mass in chow- and high fat-fed IIA+ mice was constant and similar to the BL/6 mice on a chow diet. Surprisingly, the IIA+ mice had an elevated metabolic rate, which was not due to differences in physical activity. The IIA+ mice were more insulin sensitive and glucose tolerant than the BL/6 mice, even when the IIA+ mice were provided the high fat diet. The IIA+ mice had increased expression of uncoupling protein 1 (UCP1), sirtuin 1 (SIRT1), and PPARγ coactivator 1α (PGC-1α) in brown adipose tissue (BAT), suggesting that PLA2G2A activates mitochondrial uncoupling in BAT. Our data indicate that PLA2G2A has a previously undiscovered impact on insulin sensitivity and metabolism.
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Affiliation(s)
- Michael S Kuefner
- Departments of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Veterans Affairs Medical Center, Memphis, TN
| | - Kevin Pham
- Departments of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Veterans Affairs Medical Center, Memphis, TN
| | - Jeanna R Redd
- Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Pediatrics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI
| | - Erin J Stephenson
- Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Pediatrics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN
| | - Innocence Harvey
- Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI
| | - Xiong Deng
- Departments of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Veterans Affairs Medical Center, Memphis, TN
| | - Dave Bridges
- Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Pediatrics, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI
| | - Eric Boilard
- Department of Infectious Diseases and Immunity, Faculté de Médecine de l'Université Laval, CHUQ Research Center and Division of Rheumatology, Quebec City, Canada
| | - Marshall B Elam
- Departments of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN.,Department of Veterans Affairs Medical Center, Memphis, TN
| | - Edwards A Park
- Departments of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN .,Department of Veterans Affairs Medical Center, Memphis, TN
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Lee JS, Chapman MJ, Piraino P, Lamerz J, Schindler T, Cutler P, Dernick G. Remodeling of plasma lipoproteins in patients with rheumatoid arthritis: Interleukin-6 receptor-alpha inhibition with tocilizumab. Proteomics Clin Appl 2015. [PMID: 26201085 DOI: 10.1002/prca.201500036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE Rheumatoid arthritis (RA) is associated with increased cardiovascular risk, mediated in part by elevated circulating interleukin-6 levels and proinflammatory changes in plasma lipoproteins. We hypothesized that RA patients acquire inflammation-induced modifications to the protein cargo of circulating lipoproteins that may be reversed by tocilizumab, an interleukin-6 receptor-alpha inhibitor. EXPERIMENTAL DESIGN Size-exclusion chromatography and reverse-phase protein arrays using 29 antibodies against 26 proteins were applied at baseline and after tocilizumab treatment to analyze the distributions of apolipoproteins, enzymes, lipid transfer proteins, and other associated proteins in plasma lipoprotein fractions from 20 women with RA. RESULTS A 30% reduction in high-density lipoprotein (HDL)-associated serum amyloid A4 and complement C4 occurred with tocilizumab. Levels of C-reactive protein, associated or comigrating with HDL and low-density lipoprotein (LDL) peaks, were reduced on treatment by approximately 80% and 24%, respectively. Reductions in lipoprotein-associated phospholipase A2, lipoprotein (a), and cholesteryl ester transfer protein in the LDL fraction suggest reductions in LDL-associated proatherogenic factors. Elevations in very low-density lipoprotein (VLDL) enriched with apolipoprotein E were equally observed. CONCLUSIONS AND CLINICAL RELEVANCE Tocilizumab treatment led to reductions in proinflammatory components and proatherogenic proteins associated with HDL. Whether changes in the proteome of VLDL, LDL, and HDL induced by anti-inflammatory tocilizumab treatment in RA patients modify cardiovascular disease risk requires further investigation.
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Affiliation(s)
| | - M John Chapman
- INSERM Dyslipidemia and Atherosclerosis Research Unit, Pitié-Salpêtrière University Hospital, Paris, France
| | | | - Jens Lamerz
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche AG, Basel, Switzerland
| | - Thomas Schindler
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche AG, Basel, Switzerland
| | - Paul Cutler
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche AG, Basel, Switzerland
| | - Gregor Dernick
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche AG, Basel, Switzerland
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Kuivenhoven JA, Hegele RA. Mining the genome for lipid genes. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1993-2009. [PMID: 24798233 DOI: 10.1016/j.bbadis.2014.04.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/22/2014] [Accepted: 04/27/2014] [Indexed: 12/12/2022]
Abstract
Mining of the genome for lipid genes has since the early 1970s helped to shape our understanding of how triglycerides are packaged (in chylomicrons), repackaged (in very low density lipoproteins; VLDL), and hydrolyzed, and also how remnant and low-density lipoproteins (LDL) are cleared from the circulation. Gene discoveries have also provided insights into high-density lipoprotein (HDL) biogenesis and remodeling. Interestingly, at least half of these key molecular genetic studies were initiated with the benefit of prior knowledge of relevant proteins. In addition, multiple important findings originated from studies in mouse, and from other types of non-genetic approaches. Although it appears by now that the main lipid pathways have been uncovered, and that only modulators or adaptor proteins such as those encoded by LDLRAP1, APOA5, ANGPLT3/4, and PCSK9 are currently being discovered, genome wide association studies (GWAS) in particular have implicated many new loci based on statistical analyses; these may prove to have equally large impacts on lipoprotein traits as gene products that are already known. On the other hand, since 2004 - and particularly since 2010 when massively parallel sequencing has become de rigeur - no major new insights into genes governing lipid metabolism have been reported. This is probably because the etiologies of true Mendelian lipid disorders with overt clinical complications have been largely resolved. In the meantime, it has become clear that proving the importance of new candidate genes is challenging. This could be due to very low frequencies of large impact variants in the population. It must further be emphasized that functional genetic studies, while necessary, are often difficult to accomplish, making it hazardous to upgrade a variant that is simply associated to being definitively causative. Also, it is clear that applying a monogenic approach to dissect complex lipid traits that are mostly of polygenic origin is the wrong way to proceed. The hope is that large-scale data acquisition combined with sophisticated computerized analyses will help to prioritize and select the most promising candidate genes for future research. We suggest that at this point in time, investment in sequence technology driven candidate gene discovery could be recalibrated by refocusing efforts on direct functional analysis of the genes that have already been discovered. This article is part of a Special Issue entitled: From Genome to Function.
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Affiliation(s)
- Jan Albert Kuivenhoven
- University of Groningen, University Medical Center Groningen, Department of Pediatrics, Section Molecular Genetics, Antonius Deusinglaan 1, 9713GZ Groningen, The Netherlands
| | - Robert A Hegele
- Blackburn Cardiovascular Genetics Laboratory, Robarts Research Institute, 4288A-1151 Richmond Street North, London, ON N6A 5B7, Canada
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Targeting NADPH oxidase and phospholipases A2 in Alzheimer's disease. Mol Neurobiol 2010; 41:73-86. [PMID: 20195796 DOI: 10.1007/s12035-010-8107-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 02/04/2010] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is marked by an increase in the production of extracellular beta amyloid plaques and intracellular neurofibrillary tangles associated with a decline in brain function. Increases in oxidative stress are regarded as an early sign of AD pathophysiology, although the source of reactive oxygen species (ROS) and the mechanism(s) whereby beta amyloid peptides (Abeta) impact oxidative stress have not been adequately investigated. Recent studies provide strong evidence for the involvement of NADPH oxidase and its downstream oxidative signaling pathways in the toxic effects elicited by Abeta. ROS produced by NADPH oxidase activate multiple signaling pathways leading to neuronal excitotoxicity and glial cell-mediated inflammation. This review describes recent studies demonstrating the neurotoxic effects of Abeta in conjunction with ROS produced by NADPH oxidase and the downstream pathways leading to activation of cytosolic phospholipase A(2) (PLA(2)) and secretory PLA(2). In addition, this review also describes recent studies using botanical antioxidants to protect against oxidative damage associated with AD. Investigating the metabolic and signaling pathways involving Abeta NADPH oxidase and PLA(2) can help understand the mechanisms underlying the neurodegenerative effects of oxidative stress in AD. This information should provide new therapeutic approaches for prevention of this debilitating disease.
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Divchev D, Grothusen C, Luchtefeld M, Thoenes M, Onono F, Koch R, Drexler H, Schieffer B. Impact of a combined treatment of angiotensin II type 1 receptor blockade and 3-hydroxy-3-methyl-glutaryl-CoA-reductase inhibition on secretory phospholipase A2-type IIA and low density lipoprotein oxidation in patients with coronary artery disease. Eur Heart J 2008; 29:1956-65. [DOI: 10.1093/eurheartj/ehn276] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Menschikowski M, Hagelgans A, Siegert G. Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases? Prostaglandins Other Lipid Mediat 2006; 79:1-33. [PMID: 16516807 DOI: 10.1016/j.prostaglandins.2005.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 10/29/2005] [Accepted: 10/31/2005] [Indexed: 02/07/2023]
Abstract
Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.
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Affiliation(s)
- Mario Menschikowski
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Institut für Klinische Chemie and Laboratoriumsmedizin, Fetscherstrasse 74, D-01307 Dresden, Germany.
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Abstract
PURPOSE OF REVIEW Immunohistochemistry studies have confirmed the presence of group IIA, group V and group X secretory phospholipase A2 in human or mouse atherosclerotic lesions. The possibility that secretory phospholipase A2 plays a role in the pathophysiology of atherosclerosis (and is not merely a marker for localized inflammation) has been substantiated by a number of recent in-vitro and in-vivo studies. RECENT FINDINGS A mouse strain with a targeted deletion of group V secretory phospholipase A2 has been developed. Peritoneal macrophages from these mice have significantly blunted eicosanoid generation in response to zymosan, providing the first direct evidence that a secretory phospholipase A2 plays a role in stimulation-induced arachidonic acid production in vivo. A recent in-vitro study indicated that de novo synthesized groups IIA and X secretory phospholipase A2 can mediate arachidonic acid release intracellularly, without the requirement for previous secretion from cells, as was previously thought. Several studies support the previously proposed model that secretory phospholipase A2 hydrolysis generates pro-atherogenic LDL. These data, coupled with the finding that macrophage-specific expression of human group IIA secretory phospholipase A2 promotes atherosclerotic lipid deposition in mice, draw attention to secretory phospholipase A2 as an attractive target for the treatment of atherosclerotic disease. SUMMARY Secretory phospholipase A2 activity in the arterial intima has the potential to amplify atherogenic processes by liberating potent pro-inflammatory lipid mediators and by generating pro-atherogenic LDL. Future in-vivo studies will aid in defining the mechanism(s) that underlie the pro-atherosclerotic effects of secretory phospholipase A2.
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Affiliation(s)
- Nancy R Webb
- Department of Internal Medicine, University of Kentucky, Lexington, Kentucky 40536-0200, USA.
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