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Nurden P, Stritt S, Favier R, Nurden AT. Inherited platelet diseases with normal platelet count: phenotypes, genotypes and diagnostic strategy. Haematologica 2021; 106:337-350. [PMID: 33147934 PMCID: PMC7849565 DOI: 10.3324/haematol.2020.248153] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022] Open
Abstract
Inherited platelet disorders resulting from platelet function defects and a normal platelet count cause a moderate or severe bleeding diathesis. Since the description of Glanzmann thrombasthenia resulting from defects of ITGA2B and ITGB3, new inherited platelet disorders have been discovered, facilitated by the use of high throughput sequencing and genomic analyses. Defects of RASGRP2 and FERMT3 responsible for severe bleeding syndromes and integrin activation have illustrated the critical role of signaling molecules. Important are mutations of P2RY12 encoding the major ADP receptor causal for an inherited platelet disorder with inheritance characteristics that depend on the variant identified. Interestingly, variants of GP6 encoding the major subunit of the collagen receptor GPVI/FcRassociate only with mild bleeding. The numbers of genes involved in dense granule defects including Hermansky-Pudlak and Chediak Higashi syndromes continue to progress and are updated. The ANO6 gene encoding a Ca2+-activated ion channel required for phospholipid scrambling is responsible for the rare Scott syndrome and decreased procoagulant activity. A novel EPHB2 defect in a familial bleeding syndrome demonstrates a role for this tyrosine kinase receptor independent of the classical model of its interaction with ephrins. Such advances highlight the large diversity of variants affecting platelet function but not their production, despite the difficulties in establishing a clear phenotype when few families are affected. They have provided insights into essential pathways of platelet function and have been at the origin of new and improved therapies for ischemic disease. Nevertheless, many patients remain without a diagnosis and requiring new strategies that are now discussed.
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Affiliation(s)
| | - Simon Stritt
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala
| | - Remi Favier
- French National Reference Center for Inherited Platelet Disorders, Armand Trousseau Hospital, Assistance Publique-Hôpitaux de Paris, Paris
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Chatterjee M. Platelet lipidome: Dismantling the "Trojan horse" in the bloodstream. J Thromb Haemost 2020; 18:543-557. [PMID: 31868994 DOI: 10.1111/jth.14721] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/28/2019] [Accepted: 12/16/2019] [Indexed: 02/06/2023]
Abstract
The platelet-lipid chapter in the story of atherothrombosis is an old one, recapitulated and revised in many contexts. For decades several stimulating facets have been added to it, both unraveling and increasing the perplexity of platelet-lipid interplay and its pathophysiological consequences. The recent paradigm shift in our perspective has evolved with lipidomic analysis of the intraplatelet compartment and platelet releasate. These investigations have disclosed that platelets are in constant interaction with circulatory lipids, often reflected in their lipid repertoire. In addition, they offer a shielded intracellular space for oxidative lipid metabolism generating "toxic" metabolites that escape degradation by plasma lipases and antioxidant defense, circulate undetected by conventional plasma lipid profile, and deposited at atherosclerotic lesions or thrombus. Lipidomics divulges this silent invader in platelet vehicles, thereby providing potential biomarkers of pathologic manifestations and therapeutic targets to be exploited, which is surmised in this review.
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Affiliation(s)
- Madhumita Chatterjee
- Department of Cardiology and Angiology, Internal Medicine III, University Clinic Tübingen, Tübingen, Germany
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3
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Metabolic Control of Astrocyte Pathogenic Activity via cPLA2-MAVS. Cell 2019; 179:1483-1498.e22. [PMID: 31813625 DOI: 10.1016/j.cell.2019.11.016] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 07/31/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022]
Abstract
Metabolism has been shown to control peripheral immunity, but little is known about its role in central nervous system (CNS) inflammation. Through a combination of proteomic, metabolomic, transcriptomic, and perturbation studies, we found that sphingolipid metabolism in astrocytes triggers the interaction of the C2 domain in cytosolic phospholipase A2 (cPLA2) with the CARD domain in mitochondrial antiviral signaling protein (MAVS), boosting NF-κB-driven transcriptional programs that promote CNS inflammation in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis. cPLA2 recruitment to MAVS also disrupts MAVS-hexokinase 2 (HK2) interactions, decreasing HK enzymatic activity and the production of lactate involved in the metabolic support of neurons. Miglustat, a drug used to treat Gaucher and Niemann-Pick disease, suppresses astrocyte pathogenic activities and ameliorates EAE. Collectively, these findings define a novel immunometabolic mechanism that drives pro-inflammatory astrocyte activities, outlines a new role for MAVS in CNS inflammation, and identifies candidate targets for therapeutic intervention.
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Abstract
Phospholipases are lipolytic enzymes that hydrolyze phospholipid substrates at specific ester bonds. Phospholipases are widespread in nature and play very diverse roles from aggression in snake venom to signal transduction, lipid mediator production, and metabolite digestion in humans. Phospholipases vary considerably in structure, function, regulation, and mode of action. Tremendous advances in understanding the structure and function of phospholipases have occurred in the last decades. This introductory chapter is aimed at providing a general framework of the current understanding of phospholipases and a discussion of their mechanisms of action and emerging biological functions.
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Caligiuri SPB, Parikh M, Stamenkovic A, Pierce GN, Aukema HM. Dietary modulation of oxylipins in cardiovascular disease and aging. Am J Physiol Heart Circ Physiol 2017; 313:H903-H918. [PMID: 28801523 DOI: 10.1152/ajpheart.00201.2017] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/27/2017] [Accepted: 08/05/2017] [Indexed: 01/21/2023]
Abstract
Oxylipins are a group of fatty acid metabolites generated via oxygenation of polyunsaturated fatty acids and are involved in processes such as inflammation, immunity, pain, vascular tone, and coagulation. As a result, oxylipins have been implicated in many conditions characterized by these processes, including cardiovascular disease and aging. The best characterized oxylipins in relation to cardiovascular disease are derived from the ω-6 fatty acid arachidonic acid. These oxylipins generally increase inflammation, hypertension, and platelet aggregation, although not universally. Similarly, oxylipins derived from the ω-6 fatty acid linoleic acid generally have more adverse than beneficial cardiovascular effects. Alternatively, most oxylipins derived from 20- and 22-carbon ω-3 fatty acids have anti-inflammatory, antiaggregatory, and vasodilatory effects that help explain the cardioprotective effects of these fatty acids. Much less is known regarding the oxylipins derived from the 18-carbon ω-3 fatty acid α-linolenic acid, but clinical trials with flaxseed supplementation have indicated that these oxylipins can have positive effects on blood pressure. Normal aging also is associated with changes in oxylipin levels in the brain, vasculature, and other tissues, indicating that oxylipin changes with aging may be involved in age-related changes in these tissues. A small number of trials in humans and animals with interventions that contain either 18-carbon or 20- and 22-carbon ω-3 fatty acids have indicated that dietary-induced changes in oxylipins may be beneficial in slowing the changes associated with normal aging. In summary, oxylipins are an important group of molecules amenable to dietary manipulation to target cardiovascular disease and age-related degeneration.NEW & NOTEWORTHY Oxylipins are an important group of fatty acid metabolites amenable to dietary manipulation. Because of the role they play in cardiovascular disease and in age-related degeneration, oxylipins are gaining recognition as viable targets for specific dietary interventions focused on manipulating oxylipin composition to control these biological processes.
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Affiliation(s)
- Stephanie P B Caligiuri
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Mihir Parikh
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Aleksandra Stamenkovic
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Grant N Pierce
- Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Harold M Aukema
- Department of Human Nutritional Sciences, Faculty of Agriculture and Food Sciences, University of Manitoba, Winnipeg, Manitoba, Canada; and .,Canadian Centre for Agri-food Research in Health and Medicine, Albrechtsen Research Centre, St. Boniface Hospital, Winnipeg, Manitoba, Canada
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Yun B, Leslie CC. Cellular Assays for Evaluating Calcium-Dependent Translocation of cPLA 2α to Membrane. Methods Enzymol 2016; 583:71-99. [PMID: 28063500 DOI: 10.1016/bs.mie.2016.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The group IVA phospholipase A2, commonly called cytosolic phospholipase A2α (cPLA2α), is a widely expressed enzyme that hydrolyzes membrane phospholipid to produce arachidonic acid and lysophospholipids, which are precursors for a number of bioactive lipid mediators. Arachidonic acid is metabolized through the cyclooxygenase and lipoxygenase pathways for production of prostaglandins and leukotrienes that regulate normal physiological processes and contribute to disease pathogenesis. cPLA2α is composed of an N-terminal C2 domain and a C-terminal catalytic domain that contains the Ser-Asp catalytic dyad. The catalytic domain contains phosphorylation sites and basic residues that regulate the catalytic activity of cPLA2α. In response to cell stimulation, cPLA2α is rapidly activated by posttranslational mechanisms including increases in intracellular calcium and phosphorylation by mitogen-activated protein kinases. In resting cells, cPLA2α is localized in the cytosol but translocates to membrane including the Golgi, endoplasmic reticulum, and the peri-nuclear membrane in response to increases in intracellular calcium. Calcium binds to the C2 domain, which promotes the interaction of cPLA2α with membrane through hydrophobic interactions. In this chapter, we describe assays used to study the calcium-dependent translocation of cPLA2α to membrane, a regulatory step necessary for access to phospholipid and release of arachidonic acid.
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Affiliation(s)
- B Yun
- National Jewish Health, Denver, CO, United States
| | - C C Leslie
- National Jewish Health, Denver, CO, United States; University of Colorado Denver, Aurora, CO, United States.
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Gabbs M, Leng S, Devassy JG, Monirujjaman M, Aukema HM. Advances in Our Understanding of Oxylipins Derived from Dietary PUFAs. Adv Nutr 2015; 6:513-40. [PMID: 26374175 PMCID: PMC4561827 DOI: 10.3945/an.114.007732] [Citation(s) in RCA: 462] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Oxylipins formed from polyunsaturated fatty acids (PUFAs) are the main mediators of PUFA effects in the body. They are formed via cyclooxygenase, lipoxygenase, and cytochrome P450 pathways, resulting in the formation of prostaglandins, thromboxanes, mono-, di-, and tri-hydroxy fatty acids (FAs), epoxy FAs, lipoxins, eoxins, hepoxilins, resolvins, protectins (also called neuroprotectins in the brain), and maresins. In addition to the well-known eicosanoids derived from arachidonic acid, recent developments in lipidomic methodologies have raised awareness of and interest in the large number of oxylipins formed from other PUFAs, including those from the essential FAs and the longer-chain n-3 (ω-3) PUFAs. Oxylipins have essential roles in normal physiology and function, but can also have detrimental effects. Compared with the oxylipins derived from n-3 PUFAs, oxylipins from n-6 PUFAs generally have greater activity and more inflammatory, vasoconstrictory, and proliferative effects, although there are notable exceptions. Because PUFA composition does not necessarily reflect oxylipin composition, comprehensive analysis of the oxylipin profile is necessary to understand the overall physiologic effects of PUFAs mediated through their oxylipins. These analyses should include oxylipins derived from linoleic and α-linolenic acids, because these largely unexplored bioactive oxylipins constitute more than one-half of oxylipins present in tissues. Because collated information on oxylipins formed from different PUFAs is currently unavailable, this review provides a detailed compilation of the main oxylipins formed from PUFAs and describes their functions. Much remains to be elucidated in this emerging field, including the discovery of more oxylipins, and the understanding of the differing biological potencies, kinetics, and isomer-specific activities of these novel PUFA metabolites.
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Affiliation(s)
| | | | | | | | - Harold M Aukema
- Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada; and Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Canada
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Leslie CC. Cytosolic phospholipase A₂: physiological function and role in disease. J Lipid Res 2015; 56:1386-402. [PMID: 25838312 DOI: 10.1194/jlr.r057588] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Indexed: 02/06/2023] Open
Abstract
The group IV phospholipase A2 (PLA2) family is comprised of six intracellular enzymes (GIVA, -B, -C, -D, -E, and -F) commonly referred to as cytosolic PLA2 (cPLA2)α, -β, -γ, -δ, -ε, and -ζ. They contain a Ser-Asp catalytic dyad and all except cPLA2γ have a C2 domain, but differences in their catalytic activities and subcellular localization suggest unique regulation and function. With the exception of cPLA2α, the focus of this review, little is known about the in vivo function of group IV enzymes. cPLA2α catalyzes the hydrolysis of phospholipids to arachidonic acid and lysophospholipids that are precursors of numerous bioactive lipids. The regulation of cPLA2α is complex, involving transcriptional and posttranslational processes, particularly increases in calcium and phosphorylation. cPLA2α is a highly conserved widely expressed enzyme that promotes lipid mediator production in human and rodent cells from a variety of tissues. The diverse bioactive lipids produced as a result of cPLA2α activation regulate normal physiological processes and disease pathogenesis in many organ systems, as shown using cPLA2α KO mice. However, humans recently identified with cPLA2α deficiency exhibit more pronounced effects on health than observed in mice lacking cPLA2α, indicating that much remains to be learned about this interesting enzyme.
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Affiliation(s)
- Christina C Leslie
- Department of Pediatrics, National Jewish Health, Denver, CO 80206; and Departments of Pathology and Pharmacology, University of Colorado Denver, Aurora, CO 80045
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Faioni EM, Razzari C, Zulueta A, Femia EA, Fenu L, Trinchera M, Podda GM, Pugliano M, Marongiu F, Cattaneo M. Bleeding diathesis and gastro-duodenal ulcers in inherited cytosolic phospholipase-A2 alpha deficiency. Thromb Haemost 2014; 112:1182-9. [PMID: 25102815 DOI: 10.1160/th14-04-0352] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/20/2014] [Indexed: 11/05/2022]
Abstract
Arachidonic acid (AA), when cleaved from phospholipids by cytosolic phospholipase A2 alpha (cPLA2a), generates eicosanoids, with pro-hemostatic, pro-inflammatory, vasoactive and gastro-protective functions. We describe a patient (27-year-old man) and his twin-sister with early-onset bleeding diathesis and recurrent gastro-intestinal (GI) ulcers. Platelet aggregation/δ-granules secretion by collagen was impaired, but normal by AA; serum levels of thromboxane (Tx) B2 and 12-hydroxyeicosatetraenoic acid, and urinary levels of 11-dehydro-TxB2 were extremely low. Patients were homozygous for 1723G>C transition in PLA2G4A gene, which changed the codon for Asp575 to His. GI ulcers affected 5/14 heterozygous (< 40 years) and 1/16 wild-type homozygous (> 60 years) family members; none had bleeding diathesis. The proband, his sister and mother also had mildly reduced factor XI levels. Platelet messenger RNA expression did not differ among subjects with different PLA2G4A genotypes. Conversely, platelet cPLA2a was undetectable by Western Blotting in the proband and his sister, and decreased in 1723G>C heterozygous subjects, suggesting that the variant is transcribed, but not translated or translated into an unstable protein. We described a syndromic form of deficiency of cPLA2a , characterised by recurrent GI ulcers and bleeding diathesis, associated with mild inherited deficiency of factor XI. Unlike other reported patients with cPLA2a deficiency, these patients had extremely low levels of platelet TxA2 biosynthesis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - M Cattaneo
- Marco Cattaneo, MD, Medicina 3, Ospedale San Paolo, Dipartimento di Scienze della Salute, Università degli Studi di Milano, Via A. di Rudinì, 8, 20142 Milano, Italy, Tel.: +39 02 50323188, Fax: +39 02 50323089, E-mail:
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Tourdot BE, Ahmed I, Holinstat M. The emerging role of oxylipins in thrombosis and diabetes. Front Pharmacol 2014; 4:176. [PMID: 24432004 PMCID: PMC3882718 DOI: 10.3389/fphar.2013.00176] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 12/21/2013] [Indexed: 01/08/2023] Open
Abstract
The prevalence of cardiovascular disease (CVD), the leading cause of death in the US, is predicted to increase due to the shift in age of the general population and increase in CVD risk factors such as obesity and diabetes. New therapies are required to decrease the prevalence of CVD risk factors (obesity and diabetes) as well as reduce atherothrombosis, the major cause of CVD related mortality. Oxylipins, bioactive metabolites derived from the oxygenation of polyunsaturated fatty acids, play a role in the progression of CVD risk factors and thrombosis. Aspirin, a cyclooxygenase-1 inhibitor, decreases atherothrombotic associated mortality by 25%. These potent effects of aspirin have shown the utility of modulating oxylipin signaling pathways to decrease CVD mortality. The role of many oxylipins in the progression of CVD, however, is still uncertain or controversial. An increased understanding of the role oxylipins play in CVD risk factors and thrombosis could lead to new therapies to decrease the prevalence of CVD and its associated mortality.
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Affiliation(s)
- Benjamin E Tourdot
- Cardeza Foundation for Hematologic Research, Department of Medicine, Thomas Jefferson University Philadelphia PA, USA
| | - Intekhab Ahmed
- Division of Endocrinology, Diabetes and Metabolic Diseases, Department of Medicine, Thomas Jefferson University Philadelphia PA, USA
| | - Michael Holinstat
- Cardeza Foundation for Hematologic Research, Department of Medicine, Thomas Jefferson University Philadelphia PA, USA
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Pniewska E, Pawliczak R. The involvement of phospholipases A2 in asthma and chronic obstructive pulmonary disease. Mediators Inflamm 2013; 2013:793505. [PMID: 24089590 PMCID: PMC3780701 DOI: 10.1155/2013/793505] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 01/02/2013] [Accepted: 02/27/2013] [Indexed: 12/21/2022] Open
Abstract
The increased morbidity, mortality, and ineffective treatment associated with the pathogenesis of chronic inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD) have generated much research interest. The key role is played by phospholipases from the A2 superfamily: enzymes which are involved in inflammation through participation in pro- and anti-inflammatory mediators production and have an impact on many immunocompetent cells. The 30 members of the A2 superfamily are divided into 7 groups. Their role in asthma and COPD has been studied in vitro and in vivo (animal models, cell cultures, and patients). This paper contains complete and updated information about the involvement of particular enzymes in the etiology and course of asthma and COPD.
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Affiliation(s)
- Ewa Pniewska
- Department of Immunopathology, Faculty of Biomedical Sciences and Postgraduate Training, Medical University of Lodz, 7/9 Zeligowskiego Street, Building 2, Room 122, 90-752 Lodz, Poland
| | - Rafal Pawliczak
- Department of Immunopathology, Faculty of Biomedical Sciences and Postgraduate Training, Medical University of Lodz, 7/9 Zeligowskiego Street, Building 2, Room 122, 90-752 Lodz, Poland
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Qin SS, Yu YX, Li QK, Yu ZW. Interaction of Human Synovial Phospholipase A2 with Mixed Lipid Bilayers: A Coarse-Grain and All-Atom Molecular Dynamics Simulation Study. Biochemistry 2013; 52:1477-89. [DOI: 10.1021/bi3012687] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shan-Shan Qin
- Key Laboratory of Bioorganic
Phosphorous Chemistry and Chemical Biology (Ministry of Education),
Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
| | - Yang-Xin Yu
- Laboratory of Chemical Engineering
Thermodynamics, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Qi-Kai Li
- Department of Mechanical Engineering, Tsinghua University, Beijing 100084, P. R. China
| | - Zhi-Wu Yu
- Key Laboratory of Bioorganic
Phosphorous Chemistry and Chemical Biology (Ministry of Education),
Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China
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Tanaka K, Siddiqi NJ, Alhomida AS, Farooqui AA, Ong WY. Differential regulation of cPLA2 and iPLA2 expression in the brain. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11515-012-9247-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hartiala J, Gilliam E, Vikman S, Campos H, Allayee H. Association of PLA2G4A with myocardial infarction is modulated by dietary PUFAs. Am J Clin Nutr 2012; 95:959-65. [PMID: 22378731 PMCID: PMC3302367 DOI: 10.3945/ajcn.111.032094] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Leukotrienes are proinflammatory molecules derived from dietary PUFAs and have been associated with cardiovascular disease (CVD). We previously reported that an A→G variant (rs12746200) of the cytosolic phospholipase A2 group IVA gene (PLA2G4A), which encodes the enzyme that liberates PUFAs from cellular membranes for leukotriene synthesis, decreases the risk of CVD. OBJECTIVE We sought to replicate these initial observations with a more clinically relevant phenotype, such as myocardial infarction (MI), and to determine whether dietary PUFAs mediate this association. DESIGN In a Costa Rican case-control data set (n = 3971), rs12746200 was genotyped and was tested for an association with MI. Functional experiments were carried out to determine whether rs12746200 led to differences in mRNA expression. RESULTS Risk of MI was significantly lower in AG/GG subjects than in AA homozygotes (OR: 0.86; 95% CI: 0.75, 0.99; P = 0.040). The reduced risk of MI was observed primarily in AG/GG subjects who were above the median for intake of dietary omega-6 (n-6) PUFAs (OR: 0.71; 95% CI: 0.59, 0.87; P-interaction = 0.005). A similar analysis with dietary omega-3 (n-3) PUFAs did not show a statistically significant nutrigenetic association (P-interaction = 0.23). Functional analysis in human aortic endothelial cells showed that the carriers of the G allele had significantly lower PLA2G4A gene expression (P = 0.014), consistent with the atheroprotective association of this variant. CONCLUSION These results replicate the association of rs12746200 with CVD phenotypes and provide evidence that the protective association of this functional PLA2G4A variant is mediated by dietary PUFAs.
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Affiliation(s)
- Jaana Hartiala
- Department of Preventive Medicine, the University of Southern California Keck School of Medicine, Los Angeles, CA, USA
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Abstract
Phospholipids are present in all living organisms. They are a major component of all biological membranes, along with glycolipids and cholesterol. Enzymes aimed at cleaving the various bonds in phospholipids, namely phospholipases, are consequently widespread in nature, playing very diverse roles from aggression in snake venom to signal transduction, lipid mediators production, and digestion in humans. Although all phospholipases target phospholipids as substrates, they vary in the site of action on the phospholipids molecules, physiological function, mode of action, and their regulation. Significant studies on phospholipases characterization, physiological role, and industrial potential have been conducted worldwide. Some of them have been directed for biotechnological advances, such as gene discovery and functional enhancement by protein engineering. Others reported phospholipases as virulence factors and major causes of pathophysiological effects. In this introductory chapter, we provide brief details of different phospholipases.
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Affiliation(s)
- Ahmed Aloulou
- National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia.
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Yeung J, Apopa PL, Vesci J, Kenyon V, Rai G, Jadhav A, Simeonov A, Holman TR, Maloney DJ, Boutaud O, Holinstat M. Protein kinase C regulation of 12-lipoxygenase-mediated human platelet activation. Mol Pharmacol 2011; 81:420-30. [PMID: 22155783 DOI: 10.1124/mol.111.075630] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Platelet activation is important in the regulation of hemostasis and thrombosis. Uncontrolled activation of platelets may lead to arterial thrombosis, which is a major cause of myocardial infarction and stroke. After activation, metabolism of arachidonic acid (AA) by 12-lipoxygenase (12-LOX) may play a significant role in regulating the degree and stability of platelet activation because inhibition of 12-LOX significantly attenuates platelet aggregation in response to various agonists. Protein kinase C (PKC) activation is also known to be an important regulator of platelet activity. Using a newly developed selective inhibitor for 12-LOX and a pan-PKC inhibitor, we investigated the role of PKC in 12-LOX-mediated regulation of agonist signaling in the platelet. To determine the role of PKC within the 12-LOX pathway, a number of biochemical endpoints were measured, including platelet aggregation, calcium mobilization, and integrin activation. Inhibition of 12-LOX or PKC resulted in inhibition of dense granule secretion and attenuation of both aggregation and αIIbβ(3) activation. However, activation of PKC downstream of 12-LOX inhibition rescued agonist-induced aggregation and integrin activation. Furthermore, inhibition of 12-LOX had no effect on PKC-mediated aggregation, indicating that 12-LOX is upstream of PKC. These studies support an essential role for PKC downstream of 12-LOX activation in human platelets and suggest 12-LOX as a possible target for antiplatelet therapy.
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Affiliation(s)
- Jennifer Yeung
- Department of Medicine, Cardeza Foundation for Hematologic Research, Thomas Jefferson University, Philadelphia, PA 19107, USA
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17
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Bechler ME, de Figueiredo P, Brown WJ. A PLA1-2 punch regulates the Golgi complex. Trends Cell Biol 2011; 22:116-24. [PMID: 22130221 DOI: 10.1016/j.tcb.2011.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 12/14/2022]
Abstract
The mammalian Golgi complex, trans Golgi network (TGN) and ER-Golgi intermediate compartment (ERGIC) are comprised of membrane cisternae, coated vesicles and membrane tubules, all of which contribute to membrane trafficking and maintenance of their unique architectures. Recently, a new cast of players was discovered to regulate the Golgi and ERGIC: four unrelated cytoplasmic phospholipase A (PLA) enzymes, cPLA(2)α (GIVA cPLA(2)), PAFAH Ib (GVIII PLA(2)), iPLA(2)-β (GVIA-2 iPLA(2)) and iPLA(1)γ. These ubiquitously expressed enzymes regulate membrane trafficking from specific Golgi subcompartments, although there is evidence for some functional redundancy between PAFAH Ib and cPLA(2)α. Three of these enzymes, PAFAH Ib, cPLA(2)α and iPLA(2)-β, exert effects on Golgi structure and function by inducing the formation of membrane tubules. We review our current understanding of how PLA enzymes regulate Golgi and ERGIC morphology and function.
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Affiliation(s)
- Marie E Bechler
- Department of Molecular Biology & Genetics, Cornell University, Ithaca, NY 14853, USA
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