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The phospholipase A 2 superfamily as a central hub of bioactive lipids and beyond. Pharmacol Ther 2023; 244:108382. [PMID: 36918102 DOI: 10.1016/j.pharmthera.2023.108382] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/13/2023]
Abstract
In essence, "phospholipase A2" (PLA2) means a group of enzymes that release fatty acids and lysophospholipids by hydrolyzing the sn-2 position of glycerophospholipids. To date, more than 50 enzymes possessing PLA2 or related lipid-metabolizing activities have been identified in mammals, and these are subdivided into several families in terms of their structures, catalytic mechanisms, tissue/cellular localizations, and evolutionary relationships. From a general viewpoint, the PLA2 superfamily has mainly been implicated in signal transduction, driving the production of a wide variety of bioactive lipid mediators. However, a growing body of evidence indicates that PLA2s also contribute to phospholipid remodeling or recycling for membrane homeostasis, fatty acid β-oxidation for energy production, and barrier lipid formation on the body surface. Accordingly, PLA2 enzymes are considered one of the key regulators of a broad range of lipid metabolism, and perturbation of specific PLA2-driven lipid pathways often disrupts tissue and cellular homeostasis and may be associated with a variety of diseases. This review covers current understanding of the physiological functions of the PLA2 superfamily, focusing particularly on the two major intracellular PLA2 families (Ca2+-dependent cytosolic PLA2s and Ca2+-independent patatin-like PLA2s) as well as other PLA2 families, based on studies using gene-manipulated mice and human diseases in combination with comprehensive lipidomics.
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2
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Abstract
Mitochondria of all tissues convert various metabolic substrates into two forms of energy: ATP and heat. Historically, the primary focus of research in mitochondrial bioenergetics was on the mechanisms of ATP production, while mitochondrial thermogenesis received significantly less attention. Nevertheless, mitochondrial heat production is crucial for the maintenance of body temperature, regulation of the pace of metabolism, and prevention of oxidative damage to mitochondria and the cell. In addition, mitochondrial thermogenesis has gained significance as a pharmacological target for treating metabolic disorders. Mitochondria produce heat as the result of H+ leak across their inner membrane. This review provides a critical assessment of the current field of mitochondrial H+ leak and thermogenesis, with a focus on the molecular mechanisms involved in the function and regulation of uncoupling protein 1 and the ADP/ATP carrier, the two proteins that mediate mitochondrial H+ leak.
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Affiliation(s)
- Ambre M. Bertholet
- Department of Physiology, University of California San Francisco, 600 16 Street, San Francisco, CA 94158, USA,Department of Physiology, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA,Corresponding authors: ,
| | - Yuriy Kirichok
- Department of Physiology, University of California, San Francisco, California, USA;
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3
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Prunonosa Cervera I, Gabriel BM, Aldiss P, Morton NM. The phospholipase A2 family's role in metabolic diseases: Focus on skeletal muscle. Physiol Rep 2021; 9:e14662. [PMID: 33433056 PMCID: PMC7802192 DOI: 10.14814/phy2.14662] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 12/17/2022] Open
Abstract
The prevalence of obesity and type 2 diabetes has increased substantially in recent years creating a global health burden. In obesity, skeletal muscle, the main tissue responsible for insulin-mediated glucose uptake, exhibits dysregulation of insulin signaling, glucose uptake, lipid metabolism, and mitochondrial function, thus, promoting type 2 diabetes. The phospholipase A2 (PLA2) enzyme family mediates lipid signaling and membrane remodeling and may play an important role in metabolic disorders such as obesity, diabetes, hyperlipidemia, and fatty liver disease. The PLA2 family consists of 16 members clustered in four groups. PLA2s hydrolyze the sn-2 ester bond of phospholipids generating free fatty acids and lysophospholipids. Differential tissue and subcellular PLA2 expression patterns and the abundance of distinct fatty acyl groups in the target phospholipid determine the impact of individual family members on metabolic functions and, potentially, diseases. Here, we update the current knowledge of the role of the PLA2 family in skeletal muscle, with a view to their potential for therapeutic targeting in metabolic diseases.
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Affiliation(s)
- Iris Prunonosa Cervera
- Molecular Metabolism GroupCentre for Cardiovascular SciencesQueens Medical Research InstituteUniversity of EdinburghEdinburghUK
| | - Brendan M. Gabriel
- Molecular Metabolism GroupCentre for Cardiovascular SciencesQueens Medical Research InstituteUniversity of EdinburghEdinburghUK
- Department of Physiology and PharmacologyIntegrative PhysiologyKarolinska InstituteStockholmSweden
- Aberdeen Cardiovascular & Diabetes CentreThe Rowett InstituteUniversity of AberdeenAberdeenUK
| | - Peter Aldiss
- Molecular Metabolism GroupCentre for Cardiovascular SciencesQueens Medical Research InstituteUniversity of EdinburghEdinburghUK
| | - Nicholas M. Morton
- Molecular Metabolism GroupCentre for Cardiovascular SciencesQueens Medical Research InstituteUniversity of EdinburghEdinburghUK
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Metabolic Effects of Selective Deletion of Group VIA Phospholipase A 2 from Macrophages or Pancreatic Islet Beta-Cells. Biomolecules 2020; 10:biom10101455. [PMID: 33080873 PMCID: PMC7602969 DOI: 10.3390/biom10101455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/08/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022] Open
Abstract
To examine the role of group VIA phospholipase A2 (iPLA2β) in specific cell lineages in insulin secretion and insulin action, we prepared mice with a selective iPLA2β deficiency in cells of myelomonocytic lineage, including macrophages (MØ-iPLA2β-KO), or in insulin-secreting β-cells (β-Cell-iPLA2β-KO), respectively. MØ-iPLA2β-KO mice exhibited normal glucose tolerance when fed standard chow and better glucose tolerance than floxed-iPLA2β control mice after consuming a high-fat diet (HFD). MØ-iPLA2β-KO mice exhibited normal glucose-stimulated insulin secretion (GSIS) in vivo and from isolated islets ex vivo compared to controls. Male MØ-iPLA2β-KO mice exhibited enhanced insulin responsivity vs. controls after a prolonged HFD. In contrast, β-cell-iPLA2β-KO mice exhibited impaired glucose tolerance when fed standard chow, and glucose tolerance deteriorated further when introduced to a HFD. β-Cell-iPLA2β-KO mice exhibited impaired GSIS in vivo and from isolated islets ex vivo vs. controls. β-Cell-iPLA2β-KO mice also exhibited an enhanced insulin responsivity compared to controls. These findings suggest that MØ iPLA2β participates in HFD-induced deterioration in glucose tolerance and that this mainly reflects an effect on insulin responsivity rather than on insulin secretion. In contrast, β-cell iPLA2β plays a role in GSIS and also appears to confer some protection against deterioration in β-cell functions induced by a HFD.
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Rescue of Hepatic Phospholipid Remodeling Defectin iPLA2β-Null Mice Attenuates Obese but Not Non-Obese Fatty Liver. Biomolecules 2020; 10:biom10091332. [PMID: 32957701 PMCID: PMC7565968 DOI: 10.3390/biom10091332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/15/2020] [Accepted: 09/15/2020] [Indexed: 12/19/2022] Open
Abstract
Polymorphisms of group VIA calcium-independent phospholipase A2 (iPLA2β or PLA2G6) are positively associated with adiposity, blood lipids, and Type-2 diabetes. The ubiquitously expressed iPLA2β catalyzes the hydrolysis of phospholipids (PLs) to generate a fatty acid and a lysoPL. We studied the role of iPLA2β on PL metabolism in non-alcoholic fatty liver disease (NAFLD). By using global deletion iPLA2β-null mice, we investigated three NAFLD mouse models; genetic Ob/Ob and long-term high-fat-diet (HFD) feeding (representing obese NAFLD) as well as feeding with methionine- and choline-deficient (MCD) diet (representing non-obese NAFLD). A decrease of hepatic PLs containing monounsaturated- and polyunsaturated fatty acids and a decrease of the ratio between PLs and cholesterol esters were observed in all three NAFLD models. iPLA2β deficiency rescued these decreases in obese, but not in non-obese, NAFLD models. iPLA2β deficiency elicited protection against fatty liver and obesity in the order of Ob/Ob › HFD » MCD. Liver inflammation was not protected in HFD NAFLD, and that liver fibrosis was even exaggerated in non-obese MCD model. Thus, the rescue of hepatic PL remodeling defect observed in iPLA2β-null mice was critical for the protection against NAFLD and obesity. However, iPLA2β deletion in specific cell types such as macrophages may render liver inflammation and fibrosis, independent of steatosis protection.
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Yoda E, Hachisu K, Kuwata H, Nakatani Y, Hara S. Gene Deletion of Calcium-Independent Phospholipase A 2γ (iPLA 2γ) Suppresses Adipogenic Differentiation of Mouse Embryonic Fibroblasts. Biol Pharm Bull 2020; 43:1375-1381. [PMID: 32879212 DOI: 10.1248/bpb.b20-00321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adipogenic differentiation is a complex process by which fibroblast-like undifferentiated cells are converted into cells that accumulate lipid droplets. We here investigated the effect of gene deletion of calcium-independent phospholipase A2γ (iPLA2γ), a membrane-bound PLA2 enzyme, on adipogenic differentiation in mice. Since iPLA2γ knockout (KO) mice showed reduced fat volume and weight, we prepared mouse embryonic fibroblasts (MEF) from wild-type (WT) and iPLA2γ KO mice and examined the effect of iPLA2γ deletion on in vitro adipogenic differentiation. iPLA2γ increased during adipogenic differentiation in WT mouse-derived MEFs, and the differentiation was partially abolished in iPLA2γ KO-derived MEFs. In KO-derived MEFs, the inductions of peroxisome proliferator activator receptor γ (PPARγ) and CAAT/enhancer-binding protein α (C/EBPα) were also reduced during adipogenic differentiation, and the reductions in PPARγ and C/EBPα expressions and the defect in adipogenesis were restored by treatment with troglitazone, a PPARγ ligand. These results indicate that iPLA2γ might play a critical role in adipogenic differentiation by regulating PPARγ expression.
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Affiliation(s)
- Emiko Yoda
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University
| | - Keiko Hachisu
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University
| | - Hiroshi Kuwata
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University
| | - Yoshihito Nakatani
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University
| | - Shuntaro Hara
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University
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Funai K, Summers SA, Rutter J. Reign in the membrane: How common lipids govern mitochondrial function. Curr Opin Cell Biol 2020; 63:162-173. [PMID: 32106003 DOI: 10.1016/j.ceb.2020.01.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 12/12/2022]
Abstract
The lipids that make up biological membranes tend to be the forgotten molecules of cell biology. The paucity of data on these important entities likely reflects the difficulties of studying and understanding their biological roles, rather than revealing a lack of importance. Indeed, the lipid composition of biological membranes has a profound impact on a diverse array of cellular processes. The focus of this review is on the effects of different lipid classes on the function of mitochondria, particularly bioenergetics, in health and disease.
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Affiliation(s)
- Katsuhiko Funai
- Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA; Department of Physical Therapy & Athletic Training, University of Utah, Salt Lake City, UT, USA; Department of Nutrition & Integrative Physiology, University of Utah, Salt Lake City, UT, USA.
| | - Scott A Summers
- Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA; Department of Nutrition & Integrative Physiology, University of Utah, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
| | - Jared Rutter
- Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA; Department of Nutrition & Integrative Physiology, University of Utah, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah, Salt Lake City, UT, USA; Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT, USA.
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8
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Elimam H, Papillon J, Guillemette J, Navarro-Betancourt JR, Cybulsky AV. Genetic Ablation of Calcium-independent Phospholipase A 2γ Exacerbates Glomerular Injury in Adriamycin Nephrosis in Mice. Sci Rep 2019; 9:16229. [PMID: 31700134 PMCID: PMC6838178 DOI: 10.1038/s41598-019-52834-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/23/2019] [Indexed: 02/06/2023] Open
Abstract
Genetic ablation of calcium-independent phospholipase A2γ (iPLA2γ) in mice results in marked damage of mitochondria and enhanced autophagy in glomerular visceral epithelial cells (GECs) or podocytes. The present study addresses the role of iPLA2γ in glomerular injury. In adriamycin nephrosis, deletion of iPLA2γ exacerbated albuminuria and reduced podocyte number. Glomerular LC3-II increased and p62 decreased in adriamycin-treated iPLA2γ knockout (KO) mice, compared with treated control, in keeping with increased autophagy in KO. iPLA2γ KO GECs in culture also demonstrated increased autophagy, compared with control GECs. iPLA2γ KO GECs showed a reduced oxygen consumption rate and increased phosphorylation of AMP kinase (pAMPK), consistent with mitochondrial dysfunction. Adriamycin further stimulated pAMPK and autophagy. After co-transfection of GECs with mito-YFP (to label mitochondria) and RFP-LC3 (to label autophagosomes), or RFP-LAMP1 (to label lysosomes), there was greater colocalization of mito-YFP with RFP-LC3-II and with RFP-LAMP1 in iPLA2γ KO GECs, compared with WT, indicating enhanced mitophagy in KO. Adriamycin increased mitophagy in WT cells. Thus, iPLA2γ has a cytoprotective function in the normal glomerulus and in glomerulopathy, as deletion of iPLA2γ leads to mitochondrial damage and impaired energy homeostasis, as well as autophagy and mitophagy.
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Affiliation(s)
- Hanan Elimam
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada.,Department of Biochemistry, Faculty of Pharmacy, University of Sadat City, Monufia, Egypt
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - José R Navarro-Betancourt
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada.
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The role of cardiolipin concentration and acyl chain composition on mitochondrial inner membrane molecular organization and function. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1039-1052. [PMID: 30951877 DOI: 10.1016/j.bbalip.2019.03.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/19/2019] [Accepted: 03/30/2019] [Indexed: 12/28/2022]
Abstract
Cardiolipin (CL) is a key phospholipid of the mitochondria. A loss of CL content and remodeling of CL's acyl chains is observed in several pathologies. Strong shifts in CL concentration and acyl chain composition would presumably disrupt mitochondrial inner membrane biophysical organization. However, it remains unclear in the literature as to which is the key regulator of mitochondrial membrane biophysical properties. We review the literature to discriminate the effects of CL concentration and acyl chain composition on mitochondrial membrane organization. A widely applicable theme emerges across several pathologies, including cardiovascular diseases, diabetes, Barth syndrome, and neurodegenerative ailments. The loss of CL, often accompanied by increased levels of lyso-CLs, impairs mitochondrial inner membrane organization. Modest remodeling of CL acyl chains is not a major driver of impairments and only in cases of extreme remodeling is there an influence on membrane properties.
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10
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Turk J, White TD, Nelson AJ, Lei X, Ramanadham S. iPLA 2β and its role in male fertility, neurological disorders, metabolic disorders, and inflammation. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:846-860. [PMID: 30408523 DOI: 10.1016/j.bbalip.2018.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023]
Abstract
The Ca2+-independent phospholipases, designated as group VI iPLA2s, also referred to as PNPLAs due to their shared homology with patatin, include the β, γ, δ, ε, ζ, and η forms of the enzyme. The iPLA2s are ubiquitously expressed, share a consensus GXSXG catalytic motif, and exhibit organelle/cell-specific localization. Among the iPLA2s, iPLA2β has received wide attention as it is recognized to be involved in membrane remodeling, cell proliferation, cell death, and signal transduction. Ongoing studies implicate participation of iPLA2β in a variety of disease processes including cancer, cardiovascular abnormalities, glaucoma, and peridonditis. This review will focus on iPLA2β and its links to male fertility, neurological disorders, metabolic disorders, and inflammation.
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Affiliation(s)
- John Turk
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Tayleur D White
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Alexander J Nelson
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Xiaoyong Lei
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America; Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, United States of America.
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Hara S, Yoda E, Sasaki Y, Nakatani Y, Kuwata H. Calcium-independent phospholipase A 2γ (iPLA 2γ) and its roles in cellular functions and diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:861-868. [PMID: 30391710 DOI: 10.1016/j.bbalip.2018.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/18/2022]
Abstract
Calcium-independent phospholipase A2γ (iPLA2γ)/patatin-like phospholipase domain-containing lipase 8 (PNPLA8) is one of the iPLA2 enzymes, which do not require Ca2+ ion for their activity. iPLA2γ is a membrane-bound enzyme with unique features, including the utilization of four distinct translation initiation sites and the presence of mitochondrial and peroxisomal localization signals. This enzyme is preferentially distributed in the mitochondria and peroxisomes and is thought to be responsible for the maintenance of lipid homeostasis in these organelles. Thus, both the overexpression and the deletion of iPLA2γ in vivo caused mitochondrial abnormalities and dysfunction. Roles of iPLA2γ in lipid mediator production and cytoprotection against oxidative stress have also been suggested by in vitro and in vivo studies. The dysregulation of iPLA2γ can therefore be a critical factor in the development of many diseases, including metabolic diseases and cancer. In this review, we provide an overview of the biochemical properties of iPLA2γ and then summarize the current understanding of the in vivo roles of iPLA2γ revealed by knockout mouse studies.
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Affiliation(s)
- Shuntaro Hara
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Tokyo 142-8555, Japan.
| | - Emiko Yoda
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Tokyo 142-8555, Japan
| | - Yuka Sasaki
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Tokyo 142-8555, Japan
| | - Yoshihito Nakatani
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Tokyo 142-8555, Japan
| | - Hiroshi Kuwata
- Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Tokyo 142-8555, Japan
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Drecourt A, Babdor J, Dussiot M, Petit F, Goudin N, Garfa-Traoré M, Habarou F, Bole-Feysot C, Nitschké P, Ottolenghi C, Metodiev MD, Serre V, Desguerre I, Boddaert N, Hermine O, Munnich A, Rötig A. Impaired Transferrin Receptor Palmitoylation and Recycling in Neurodegeneration with Brain Iron Accumulation. Am J Hum Genet 2018; 102:266-277. [PMID: 29395073 DOI: 10.1016/j.ajhg.2018.01.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/05/2018] [Indexed: 12/29/2022] Open
Abstract
Neurodegeneration with brain iron accumulation (NBIA) is a genetically heterogeneous condition characterized by progressive dystonia with iron accumulation in the basal ganglia. How NBIA-associated mutations trigger iron overload remains poorly understood. After studying fibroblast cell lines from subjects carrying both known and unreported biallelic mutations in CRAT and REPS1, we ascribe iron overload to the abnormal recycling of transferrin receptor (TfR1) and the reduction of TfR1 palmitoylation in NBIA. Moreover, we describe palmitoylation as a hitherto unreported level of post-translational TfR1 regulation. A widely used antimalarial agent, artesunate, rescued abnormal TfR1 palmitoylation in cultured fibroblasts of NBIA subjects. These observations suggest therapeutic strategies aimed at targeting impaired TfR1 recycling and palmitoylation in NBIA.
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MURAKAMI M. Lipoquality control by phospholipase A 2 enzymes. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:677-702. [PMID: 29129849 PMCID: PMC5743847 DOI: 10.2183/pjab.93.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The phospholipase A2 (PLA2) family comprises a group of lipolytic enzymes that typically hydrolyze the sn-2 position of glycerophospholipids to give rise to fatty acids and lysophospholipids. The mammalian genome encodes more than 50 PLA2s or related enzymes, which are classified into several subfamilies on the basis of their structures and functions. From a general viewpoint, the PLA2 family has mainly been implicated in signal transduction, producing bioactive lipid mediators derived from fatty acids and lysophospholipids. Recent evidence indicates that PLA2s also contribute to phospholipid remodeling for membrane homeostasis or energy production for fatty acid β-oxidation. Accordingly, PLA2 enzymes can be regarded as one of the key regulators of the quality of lipids, which I herein refer to as lipoquality. Disturbance of PLA2-regulated lipoquality hampers tissue and cellular homeostasis and can be linked to various diseases. Here I overview the current state of understanding of the classification, enzymatic properties, and physiological functions of the PLA2 family.
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Affiliation(s)
- Makoto MURAKAMI
- Laboratory of Environmental and Metabolic Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- Lipid Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
- Correspondence should be addressed: M. Murakami, Laboratory of Environmental and Metabolic Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan (e-mail: )
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Heden TD, Neufer PD, Funai K. Looking Beyond Structure: Membrane Phospholipids of Skeletal Muscle Mitochondria. Trends Endocrinol Metab 2016; 27:553-562. [PMID: 27370525 PMCID: PMC4958499 DOI: 10.1016/j.tem.2016.05.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/23/2016] [Accepted: 05/26/2016] [Indexed: 12/21/2022]
Abstract
Skeletal muscle mitochondria are highly dynamic and are capable of tremendous expansion to meet cellular energetic demands. Such proliferation in mitochondrial mass requires a synchronized supply of enzymes and structural phospholipids. While transcriptional regulation of mitochondrial enzymes has been extensively studied, there is limited information on how mitochondrial membrane lipids are generated in skeletal muscle. Herein we describe how each class of phospholipids that constitute mitochondrial membranes are synthesized and/or imported, and summarize genetic evidence indicating that membrane phospholipid composition represents a significant modulator of skeletal muscle mitochondrial respiratory function. We also discuss how skeletal muscle mitochondrial phospholipids may mediate the effect of diet and exercise on oxidative metabolism.
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Affiliation(s)
- Timothy D Heden
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Kinesiology, East Carolina University, Greenville, NC, USA
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Physiology, East Carolina University, Greenville, NC, USA
| | - Katsuhiko Funai
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Kinesiology, East Carolina University, Greenville, NC, USA; Department of Physiology, East Carolina University, Greenville, NC, USA.
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15
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Deng X, Wang J, Jiao L, Utaipan T, Tuma-Kellner S, Schmitz G, Liebisch G, Stremmel W, Chamulitrat W. iPLA2β deficiency attenuates obesity and hepatic steatosis in ob/ob mice through hepatic fatty-acyl phospholipid remodeling. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:449-61. [PMID: 26873633 DOI: 10.1016/j.bbalip.2016.02.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/01/2016] [Accepted: 02/06/2016] [Indexed: 01/12/2023]
Abstract
PLA2G6 or GVIA calcium-independent PLA2 (iPLA2β) is identified as one of the NAFLD modifier genes in humans, and thought to be a target for NAFLD therapy. iPLA2β is known to play a house-keeping role in phospholipid metabolism and remodeling. However, its role in NAFLD pathogenesis has not been supported by results obtained from high-fat feeding of iPLA2β-null (PKO) mice. Unlike livers of human NAFLD and genetically obese rodents, fatty liver induced by high-fat diet is not associated with depletion of hepatic phospholipids. We therefore tested whether iPLA2β could regulate obesity and hepatic steatosis in leptin-deficient mice by cross-breeding PKO with ob/ob mice to generate ob/ob-PKO mice. Here we observed an improvement in ob/ob-PKO mice with significant reduction in serum enzymes, lipids, glucose, insulin as well as improved glucose tolerance, and reduction in islet hyperplasia. The improvement in hepatic steatosis measured by liver triglycerides, fatty acids and cholesterol esters was associated with decreased expression of PPARγ and de novo lipogenesis genes, and the reversal of β-oxidation gene expression. Notably, ob/ob livers contained depleted levels of lysophospholipids and phospholipids, and iPLA2β deficiency in ob/ob-PKO livers lowers the former, but replenished the latter particularly phosphatidylethanolamine (PE) and phosphatidylcholine (PC) that contained arachidonic (AA) and docosahexaenoic (DHA) acids. Compared with WT livers, PKO livers also contained increased PE and PC containing AA and DHA. Thus, iPLA2β deficiency protected against obesity and ob/ob fatty liver which was associated with hepatic fatty-acyl phospholipid remodeling. Our results support the deleterious role of iPLA2β in severe obesity associated NAFLD.
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Affiliation(s)
- Xiuling Deng
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430022 Wuhan, China
| | - Jiliang Wang
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Li Jiao
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Tanyarath Utaipan
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Gerd Schmitz
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Wolfgang Stremmel
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University of Heidelberg Hospital, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
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Greene NP, Lee DE, Brown JL, Rosa ME, Brown LA, Perry RA, Henry JN, Washington TA. Mitochondrial quality control, promoted by PGC-1α, is dysregulated by Western diet-induced obesity and partially restored by moderate physical activity in mice. Physiol Rep 2015; 3:3/7/e12470. [PMID: 26177961 PMCID: PMC4552545 DOI: 10.14814/phy2.12470] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Skeletal muscle mitochondrial degeneration is a hallmark of insulin resistance/obesity marked by lost function, enhanced ROS emission, and altered morphology which may be ameliorated by physical activity (PA). However, no prior report has examined mitochondrial quality control regulation throughout biogenesis, fusion/fission dynamics, autophagy, and mitochondrial permeability transition pore (MPTP) in obesity. Therefore, we determined how each process is impacted by Western diet (WD)-induced obesity and whether voluntary PA may alleviate derangements in mitochondrial quality control mechanisms. Despite greater mitochondrial content following WD (COX-IV and Cytochrome C), induction of biogenesis controllers appears impaired (failed induction of PGC-1α). Mitochondrial fusion seems diminished (reduced MFN2, Opa1 proteins), with no significant changes in fission, suggesting a shift in balance of dynamics regulation favoring fission. Autophagy flux was promoted in WD (reduced p62, increased LC3II:I ratio); however, mitophagy marker BNIP3 is reduced in WD which may indicate reduced mitophagy despite enhanced total autophagy flux. MPTP regulator Ant mRNA is reduced by WD. Few processes were impacted by physical activity. Finally, mitochondrial quality control processes are partially promoted by PGC-1α, as PGC-1α transgenic mice display elevated mitochondrial biogenesis and autophagy flux. Additionally, these mice exhibit elevated Mfn1 and Opa1 mRNA, with no change in protein content suggesting these factors are transcriptionally promoted by PGC-1α overexpression. These data demonstrate dysfunctions across mitochondrial quality control in obesity and that PGC-1α is sufficient to promote multiple, but not necessarily all, aspects of mitochondrial quality control. Mitochondrial quality control may therefore be an opportune target to therapeutically treat metabolic disease.
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Affiliation(s)
- Nicholas P Greene
- Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - David E Lee
- Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Jacob L Brown
- Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Megan E Rosa
- Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Lemuel A Brown
- Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Richard A Perry
- Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Jordyn N Henry
- Integrative Muscle Metabolism Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
| | - Tyrone A Washington
- Exercise Muscle Biology Laboratory, Human Performance Laboratory, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, Arkansas
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Ramanadham S, Ali T, Ashley JW, Bone RN, Hancock WD, Lei X. Calcium-independent phospholipases A2 and their roles in biological processes and diseases. J Lipid Res 2015; 56:1643-68. [PMID: 26023050 DOI: 10.1194/jlr.r058701] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Indexed: 12/24/2022] Open
Abstract
Among the family of phospholipases A2 (PLA2s) are the Ca(2+)-independent PLA2s (iPLA2s) and they are designated group VI iPLA2s. In relation to secretory and cytosolic PLA2s, the iPLA2s are more recently described and details of their expression and roles in biological functions are rapidly emerging. The iPLA2s or patatin-like phospholipases (PNPLAs) are intracellular enzymes that do not require Ca(2+) for activity, and contain lipase (GXSXG) and nucleotide-binding (GXGXXG) consensus sequences. Though nine PNPLAs have been recognized, PNPLA8 (membrane-associated iPLA2γ) and PNPLA9 (cytosol-associated iPLA2β) are the most widely studied and understood. The iPLA2s manifest a variety of activities in addition to phospholipase, are ubiquitously expressed, and participate in a multitude of biological processes, including fat catabolism, cell differentiation, maintenance of mitochondrial integrity, phospholipid remodeling, cell proliferation, signal transduction, and cell death. As might be expected, increased or decreased expression of iPLA2s can have profound effects on the metabolic state, CNS function, cardiovascular performance, and cell survival; therefore, dysregulation of iPLA2s can be a critical factor in the development of many diseases. This review is aimed at providing a general framework of the current understanding of the iPLA2s and discussion of the potential mechanisms of action of the iPLA2s and related involved lipid mediators.
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Affiliation(s)
- Sasanka Ramanadham
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Tomader Ali
- Undergraduate Research Office, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jason W Ashley
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104
| | - Robert N Bone
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - William D Hancock
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xiaoyong Lei
- Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294 Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
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Metabolomic profiling in liver of adiponectin-knockout mice uncovers lysophospholipid metabolism as an important target of adiponectin action. Biochem J 2015; 469:71-82. [PMID: 25915851 DOI: 10.1042/bj20141455] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 04/27/2015] [Indexed: 12/21/2022]
Abstract
Adiponectin mediates anti-diabetic effects via increasing hepatic insulin sensitivity and direct metabolic effects. In the present study, we conducted a comprehensive and unbiased metabolomic profiling of liver tissue from AdKO (adiponectin-knockout) mice, with and without adiponectin supplementation, fed on an HFD (high-fat diet) to derive insight into the mechanisms and consequences of insulin resistance. Hepatic lipid accumulation and insulin resistance induced by the HFD were reduced by adiponectin. The HFD significantly altered levels of 147 metabolites, and bioinformatic analysis indicated that one of the most striking changes was the profile of increased lysophospholipids. These changes were largely corrected by adiponectin, at least in part via direct regulation of PLA2 (phospholipase A2) as palmitate-induced PLA2 activation was attenuated by adiponectin in primary hepatocytes. Notable decreases in several glycerolipids after the HFD were reversed by adiponectin, which also corrected elevations in several diacyglycerol and ceramide species. Our data also indicate that stimulation of ω-oxidation of fatty acids by the HFD is enhanced by adiponectin. In conclusion, this metabolomic profiling approach in AdKO mice identified important targets of adiponectin action, including PLA2, to regulate lysophospholipid metabolism and ω-oxidation of fatty acids.
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McCaffery JM, Papandonatos GD, Huggins GS, Peter I, Erar B, Kahn SE, Knowler WC, Lipkin EW, Kitabchi AE, Wagenknecht LE, Wing RR. Human cardiovascular disease IBC chip-wide association with weight loss and weight regain in the look AHEAD trial. Hum Hered 2013; 75:160-74. [PMID: 24081232 PMCID: PMC4257841 DOI: 10.1159/000353181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/AIMS The present study identified genetic predictors of weight change during behavioral weight loss treatment. METHODS Participants were 3,899 overweight/obese individuals with type 2 diabetes from Look AHEAD, a randomized controlled trial to determine the effects of intensive lifestyle intervention (ILI), including weight loss and physical activity, relative to diabetes support and education, on cardiovascular outcomes. Analyses focused on associations of single nucleotide polymorphisms (SNPs) on the Illumina CARe iSelect (IBC) chip (minor allele frequency >5%; n = 31,959) with weight change at year 1 and year 4, and weight regain at year 4, among individuals who lost ≥ 3% at year 1. RESULTS Two novel regions of significant chip-wide association with year-1 weight loss in ILI were identified (p < 2.96E-06). ABCB11 rs484066 was associated with 1.16 kg higher weight per minor allele at year 1, whereas TNFRSF11A, or RANK, rs17069904 was associated with 1.70 kg lower weight per allele at year 1. CONCLUSIONS This study, the largest to date on genetic predictors of weight loss and regain, indicates that SNPs within ABCB11, related to bile salt transfer, and TNFRSF11A, implicated in adipose tissue physiology, predict the magnitude of weight loss during behavioral intervention. These results provide new insights into potential biological mechanisms and may ultimately inform weight loss treatment.
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Affiliation(s)
- Jeanne M McCaffery
- Weight Control and Diabetes Research Center, Department of Psychiatry and Human Behavior, The Miriam Hospital and Brown Medical School, Providence, R.I., USA
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Saab-Aoudé S, Bron AM, Creuzot-Garcher CP, Bretillon L, Acar N. A mouse model of in vivo chemical inhibition of retinal calcium-independent phospholipase A2 (iPLA2). Biochimie 2013; 95:903-11. [DOI: 10.1016/j.biochi.2012.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/11/2012] [Indexed: 10/27/2022]
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Hardwick JP, Eckman K, Lee YK, Abdelmegeed MA, Esterle A, Chilian WM, Chiang JY, Song BJ. Eicosanoids in metabolic syndrome. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 66:157-266. [PMID: 23433458 DOI: 10.1016/b978-0-12-404717-4.00005-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chronic persistent inflammation plays a significant role in disease pathology of cancer, cardiovascular disease, and metabolic syndrome (MetS). MetS is a constellation of diseases that include obesity, diabetes, hypertension, dyslipidemia, hypertriglyceridemia, and hypercholesterolemia. Nonalcoholic fatty liver disease (NAFLD) is associated with many of the MetS diseases. These metabolic derangements trigger a persistent inflammatory cascade, which includes production of lipid autacoids (eicosanoids) that recruit immune cells to the site of injury and subsequent expression of cytokines and chemokines that amplify the inflammatory response. In acute inflammation, the transcellular synthesis of antiinflammatory eicosanoids resolve inflammation, while persistent activation of the autacoid-cytokine-chemokine cascade in metabolic disease leads to chronic inflammation and accompanying tissue pathology. Many drugs targeting the eicosanoid pathways have been shown to be effective in the treatment of MetS, suggesting a common linkage between inflammation, MetS and drug metabolism. The cross-talk between inflammation and MetS seems apparent because of the growing evidence linking immune cell activation and metabolic disorders such as insulin resistance, dyslipidemia, and hypertriglyceridemia. Thus modulation of lipid metabolism through either dietary adjustment or selective drugs may become a new paradigm in the treatment of metabolic disorders. This review focuses on the mechanisms linking eicosanoid metabolism to persistent inflammation and altered lipid and carbohydrate metabolism in MetS.
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Affiliation(s)
- James P Hardwick
- Biochemistry and Molecular Pathology, Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio, USA.
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Group VIB Phospholipase A(2) promotes proliferation of INS-1 insulinoma cells and attenuates lipid peroxidation and apoptosis induced by inflammatory cytokines and oxidant agents. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:989372. [PMID: 23213352 PMCID: PMC3503447 DOI: 10.1155/2012/989372] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/20/2012] [Indexed: 01/09/2023]
Abstract
Group VIB Phospholipase A(2) (iPLA(2)γ) is distributed in membranous organelles in which β-oxidation occurs, that is, mitochondria and peroxisomes, and is expressed by insulin-secreting pancreatic islet β-cells and INS-1 insulinoma cells, which can be injured by inflammatory cytokines, for example, IL-1β and IFN-γ, and by oxidants, for example, streptozotocin (STZ) or t-butyl-hydroperoxide (TBHP), via processes pertinent to mechanisms of β-cell loss in types 1 and 2 diabetes mellitus. We find that incubating INS-1 cells with IL-1β and IFN-γ, with STZ, or with TBHP causes increased expression of iPLA(2)γ mRNA and protein. We prepared INS-1 knockdown (KD) cell lines with reduced iPLA(2)γ expression, and they proliferate more slowly than control INS-1 cells and undergo increased membrane peroxidation in response to cytokines or oxidants. Accumulation of oxidized phospholipid molecular species in STZ-treated INS-1 cells was demonstrated by LC/MS/MS scanning, and the levels in iPLA(2)γ-KD cells exceeded those in control cells. iPLA(2)γ-KD INS-1 cells also exhibited higher levels of apoptosis than control cells when incubated with STZ or with IL-1β and IFN-γ. These findings suggest that iPLA(2)γ promotes β-cell proliferation and that its expression is increased during inflammation or oxidative stress as a mechanism to mitigate membrane injury that may enhance β-cell survival.
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Iyer A, Lim J, Poudyal H, Reid RC, Suen JY, Webster J, Prins JB, Whitehead JP, Fairlie DP, Brown L. An inhibitor of phospholipase A2 group IIA modulates adipocyte signaling and protects against diet-induced metabolic syndrome in rats. Diabetes 2012; 61:2320-9. [PMID: 22923652 PMCID: PMC3425408 DOI: 10.2337/db11-1179] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Obesity, type 2 diabetes, and cardiovascular disease correlate with infiltration to adipose tissue of different immune cells, with uncertain influences on metabolism. Rats were fed a diet high in carbohydrates and saturated fats to develop diet-induced obesity over 16 weeks. This nutritional overload caused overexpression and secretion of phospholipase A(2) group IIA (pla2g2a) from immune cells in adipose tissue rather than adipocytes, whereas expression of adipose-specific phospholipase A(2) (pla2g16) was unchanged. These immune cells produce prostaglandin E(2) (PGE(2)), which influences adipocyte signaling. We found that a selective inhibitor of human pla2g2a (5-(4-benzyloxyphenyl)-(4S)-(phenyl-heptanoylamino)-pentanoic acid [KH064]) attenuated secretion of PGE(2) from human immune cells stimulated with the fatty acid, palmitic acid, or with lipopolysaccharide. Oral administration of KH064 (5 mg/kg/day) to rats fed the high-carbohydrate, high-fat diet prevented the overexpression of pla2g2a and the increased macrophage infiltration and elevated PGE(2) concentrations in adipose tissue. The treatment also attenuated visceral adiposity and reversed most characteristics of metabolic syndrome, producing marked improvements in insulin sensitivity, glucose intolerance, and cardiovascular abnormalities. We suggest that pla2g2a may have a causal relationship with chronic adiposity and metabolic syndrome and that its inhibition in vivo may be a valuable new approach to treat obesity, type 2 diabetes, and metabolic dysfunction in humans.
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Affiliation(s)
- Abishek Iyer
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Junxian Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Hemant Poudyal
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Robert C. Reid
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jacky Y. Suen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Julie Webster
- Mater Medical Research Institute (MMRI), South Brisbane, Queensland, Australia
| | - Johannes B. Prins
- Mater Medical Research Institute (MMRI), South Brisbane, Queensland, Australia
| | | | - David P. Fairlie
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
- Corresponding authors: Lindsay Brown, , and David Fairlie,
| | - Lindsay Brown
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
- Department of Biological and Physical Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia
- Corresponding authors: Lindsay Brown, , and David Fairlie,
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24
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Song H, Wohltmann M, Tan M, Bao S, Ladenson JH, Turk J. Group VIA PLA2 (iPLA2β) is activated upstream of p38 mitogen-activated protein kinase (MAPK) in pancreatic islet β-cell signaling. J Biol Chem 2012; 287:5528-41. [PMID: 22194610 PMCID: PMC3285329 DOI: 10.1074/jbc.m111.285114] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 12/21/2011] [Indexed: 01/09/2023] Open
Abstract
Group VIA phospholipase A(2) (iPLA(2)β) in pancreatic islet β-cells participates in glucose-stimulated insulin secretion and sarco(endo)plasmic reticulum ATPase (SERCA) inhibitor-induced apoptosis, and both are attenuated by pharmacologic or genetic reductions in iPLA(2)β activity and amplified by iPLA(2)β overexpression. While exploring signaling events that occur downstream of iPLA(2)β activation, we found that p38 MAPK is activated by phosphorylation in INS-1 insulinoma cells and mouse pancreatic islets, that this increases with iPLA(2)β expression level, and that it is stimulated by the iPLA(2)β reaction product arachidonic acid. The insulin secretagogue D-glucose also stimulates β-cell p38 MAPK phosphorylation, and this is prevented by the iPLA(2)β inhibitor bromoenol lactone. Insulin secretion induced by d-glucose and forskolin is amplified by overexpressing iPLA(2)β in INS-1 cells and in mouse islets, and the p38 MAPK inhibitor PD169316 prevents both responses. The SERCA inhibitor thapsigargin also stimulates phosphorylation of both β-cell MAPK kinase isoforms and p38 MAPK, and bromoenol lactone prevents both events. Others have reported that iPLA(2)β products activate Rho family G-proteins that promote MAPK kinase activation via a mechanism inhibited by Clostridium difficile toxin B, which we find to inhibit thapsigargin-induced β-cell p38 MAPK phosphorylation. Thapsigargin-induced β-cell apoptosis and ceramide generation are also prevented by the p38 MAPK inhibitor PD169316. These observations indicate that p38 MAPK is activated downstream of iPLA(2)β in β-cells incubated with insulin secretagogues or thapsigargin, that this requires prior iPLA(2)β activation, and that p38 MAPK is involved in the β-cell functional responses of insulin secretion and apoptosis in which iPLA(2)β participates.
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Affiliation(s)
- Haowei Song
- From the Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, and
| | - Mary Wohltmann
- From the Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, and
| | - Min Tan
- From the Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, and
| | - Shunzhong Bao
- From the Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, and
| | - Jack H. Ladenson
- the Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - John Turk
- From the Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, and
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25
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Yamato M, Shiba T, Ide T, Seri N, Kudo W, Ando M, Yamada KI, Kinugawa S, Tsutsui H. High-fat diet-induced obesity and insulin resistance were ameliorated via enhanced fecal bile acid excretion in tumor necrosis factor-alpha receptor knockout mice. Mol Cell Biochem 2011; 359:161-7. [PMID: 21850461 DOI: 10.1007/s11010-011-1010-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/27/2011] [Indexed: 01/23/2023]
Abstract
Tumor necrosis factor-α (TNF-α) is one of the main mediators of inflammatory response activated by fatty acids in obesity, and this signaling through TNF-α receptor (TNFR) is responsible for obesity-associated insulin resistance. Recently, TNF-α has shown to affect lipid metabolism including the regulation of lipase activity and bile acid synthesis. However, there is scanty in vivo evidence for the involvement of TNF-α in this process, and the mechanistic role of TNFR remains unclear. In this study, TNFR2 knockout mice (R2KO) and wild-type (WT) mice were fed commercial normal diet (ND) or high-fat diet (HFD) for 8 weeks. In R2KO/HFD mice, the increase in body weight and the accumulation of fat were significantly ameliorated compared with WT/HFD mice in association with the decrease in plasma total cholesterol (137.7±3.1 vs. 98.6±3.1 mg/dL, P<0.005), glucose (221.9±14.7 vs. 167.3±8.1 mg/dL, P<0.01), and insulin (5.1±0.3 vs. 3.4±0.3 ng/mL, P<0.05). Fecal excretion of lipid contents was significantly increased in R2KO mice. In R2KO/HFD mice, the decrease in hepatic cholesterol-7a-hydroxylase activity, the rate-limiting enzyme in bile acid synthesis, was inhibited (1.7±0.2 vs. 8.1±1.0 pmol/min/mg protein, P<0.01). These results suggested that HFD-induced obesity with metabolic derangements could be ameliorated in mice lacking TNF-α receptor 2 via increasing fecal bile acid and lipid content excretion. Therefore, TNF-α signaling through TNFR2 is essentially involved in the bile acid synthesis and excretion of lipids, resulting in its beneficial effects.
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Affiliation(s)
- Mayumi Yamato
- Department REDOX Medicinal Science, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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26
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Abstract
PURPOSE OF REVIEW To summarize currently available information about the mechanisms involved in liver fat accumulation. RECENT FINDINGS The contribution of functional genomics approaches, such as those represented by high-throughput analysis and genetically modified mice, may envision a complex network involving fatty acid, triglyceride and phospholipid metabolisms and lipid droplet dynamics. Likewise, it may pose an exquisite regulation exerted through insulin, glucocorticoids, thyroid hormones, transcription factors and microRNAs, orchestrated with sexual differences and able to respond to environmental factors such as nutritional or viral influences among others. SUMMARY The information gathered will facilitate further research to complete gaps of interacting pieces among regulators and new contributing agents emerging from high-throughput analyses. With this new paradigm, new biomarkers able to discriminate the progression of hepatic steatosis into human steatohepatitis will eventually emerge, and hopefully new therapeutic approaches will be developed.
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Affiliation(s)
- José M Lou-Bonafonte
- Departamento de Farmacología y Fisiología, Facultad de Ciencias de Salud y del Deporte, Instituto de Investigación Sanitaria de Aragón, Universidad de Zaragoza, Zaragoza, Spain
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27
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Han MS, Lim YM, Quan W, Kim JR, Chung KW, Kang M, Kim S, Park SY, Han JS, Park SY, Cheon HG, Dal Rhee S, Park TS, Lee MS. Lysophosphatidylcholine as an effector of fatty acid-induced insulin resistance. J Lipid Res 2011; 52:1234-1246. [PMID: 21447485 DOI: 10.1194/jlr.m014787] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The mechanism of FFA-induced insulin resistance is not fully understood. We have searched for effector molecules(s) in FFA-induced insulin resistance. Palmitic acid (PA) but not oleic acid (OA) induced insulin resistance in L6 myotubes through C-Jun N-terminal kinase (JNK) and insulin receptor substrate 1 (IRS-1) Ser307 phosphorylation. Inhibitors of ceramide synthesis did not block insulin resistance by PA. However, inhibition of the conversion of PA to lysophosphatidylcholine (LPC) by calcium-independent phospholipase A₂ (iPLA₂) inhibitors, such as bromoenol lactone (BEL) or palmitoyl trifluoromethyl ketone (PACOCF₃), prevented insulin resistance by PA. iPLA₂ inhibitors or iPLA₂ small interfering RNA (siRNA) attenuated JNK or IRS-1 Ser307 phosphorylation by PA. PA treatment increased LPC content, which was reversed by iPLA₂ inhibitors or iPLA₂ siRNA. The intracellular DAG level was increased by iPLA₂ inhibitors, despite ameliorated insulin resistance. Pertussis toxin (PTX), which inhibits LPC action through the G-protein coupled receptor (GPCR)/Gα(i), reversed insulin resistance by PA. BEL administration ameliorated insulin resistance and diabetes in db/db mice. JNK and IRS-1Ser307 phosphorylation in the liver and muscle of db/db mice was attenuated by BEL. LPC content was increased in the liver and muscle of db/db mice, which was suppressed by BEL. These findings implicate LPC as an important lipid intermediate that links saturated fatty acids to insulin resistance.
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Affiliation(s)
- Myoung Sook Han
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Yu-Mi Lim
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Wenying Quan
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Jung Ran Kim
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Inchon 406-840, Korea
| | - Kun Wook Chung
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Mira Kang
- Center for Health Promotion, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Sunshin Kim
- Carcinogenesis Branch, Korean National Cancer Center, Goyang 410-769, Korea
| | - Sun Young Park
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea
| | - Joong-Soo Han
- Institute of Biomedical Science, College of Medicine, Hanyang University, Seoul 133-791, Korea; Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul 133-791, Korea
| | - Shin-Young Park
- Institute of Biomedical Science, College of Medicine, Hanyang University, Seoul 133-791, Korea; Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul 133-791, Korea
| | - Hyae Gyeong Cheon
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Inchon 406-840, Korea
| | - Sang Dal Rhee
- Bio-Organic Science Division, Korea Research Institute of Chemical Technology, Daejon 305-343, Korea
| | - Tae-Sik Park
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Inchon 406-840, Korea.
| | - Myung-Shik Lee
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
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Murakami M, Taketomi Y, Miki Y, Sato H, Hirabayashi T, Yamamoto K. Recent progress in phospholipase A₂ research: from cells to animals to humans. Prog Lipid Res 2010; 50:152-92. [PMID: 21185866 DOI: 10.1016/j.plipres.2010.12.001] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian genomes encode genes for more than 30 phospholipase A₂s (PLA₂s) or related enzymes, which are subdivided into several classes including low-molecular-weight secreted PLA₂s (sPLA₂s), Ca²+-dependent cytosolic PLA₂s (cPLA₂s), Ca²+-independent PLA₂s (iPLA₂s), platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA₂s, and a recently identified adipose-specific PLA. Of these, the intracellular cPLA₂ and iPLA₂ families and the extracellular sPLA₂ family are recognized as the "big three". From a general viewpoint, cPLA₂α (the prototypic cPLA₂ plays a major role in the initiation of arachidonic acid metabolism, the iPLA₂ family contributes to membrane homeostasis and energy metabolism, and the sPLA₂ family affects various biological events by modulating the extracellular phospholipid milieus. The cPLA₂ family evolved along with eicosanoid receptors when vertebrates first appeared, whereas the diverse branching of the iPLA₂ and sPLA₂ families during earlier eukaryote development suggests that they play fundamental roles in life-related processes. During the past decade, data concerning the unexplored roles of various PLA₂ enzymes in pathophysiology have emerged on the basis of studies using knockout and transgenic mice, the use of specific inhibitors, and information obtained from analysis of human diseases caused by mutations in PLA₂ genes. This review focuses on current understanding of the emerging biological functions of PLA₂s and related enzymes.
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Affiliation(s)
- Makoto Murakami
- Lipid Metabolism Project, The Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
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Fèvre C, Bellenger S, Pierre AS, Minville M, Bellenger J, Gresti J, Rialland M, Narce M, Tessier C. The metabolic cascade leading to eicosanoid precursors--desaturases, elongases, and phospholipases A2--is altered in Zucker fatty rats. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1811:409-17. [PMID: 21172452 DOI: 10.1016/j.bbalip.2010.12.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 11/18/2010] [Accepted: 12/10/2010] [Indexed: 11/15/2022]
Abstract
Metabolic syndrome characterized by insulin resistance and obesity is accompanied by severe lipid metabolism perturbations and chronic low-grade inflammation. However, many unresolved questions remained regarding the regulation that underlie dyslipidemia, particularly the regulation of the metabolic cascade (synthesis and release) leading to eicosanoid precursors release. This study was undertaken to investigate the regulation of desaturases/elongases and phospholipases A(2) during the establishment of metabolic syndrome. Our results showed that delta-6 desaturase as well as elongase-6 expressions were upregulated in 3-month-old Zucker fatty rats as compared to lean littermates, independently of SREBP-1c activation. We also demonstrated for the first time an increase of liver group VII phospholipase A(2) gene expression in the obese animals together with a strong specific inhibition of type IVA and VIA phospholipases A(2). These results suggest that the regulation of unsaturated fatty acids biosynthesis and signalling cascade could contribute to the development of liver lipid dysregulation related to metabolic syndrome and may be considered as new potential targets in such pathological conditions.
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Affiliation(s)
- Cécile Fèvre
- INSERM UMR 866/Université de Bourgogne, Lipides Nutrition Cancer, Faculté des Sciences Gabriel, 6 Bd Gabriel, 21000 Dijon, France
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Mancuso DJ, Sims HF, Yang K, Kiebish MA, Su X, Jenkins CM, Guan S, Moon SH, Pietka T, Nassir F, Schappe T, Moore K, Han X, Abumrad NA, Gross RW. Genetic ablation of calcium-independent phospholipase A2gamma prevents obesity and insulin resistance during high fat feeding by mitochondrial uncoupling and increased adipocyte fatty acid oxidation. J Biol Chem 2010; 285:36495-510. [PMID: 20817734 DOI: 10.1074/jbc.m110.115766] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Phospholipases are critical enzyme mediators participating in many aspects of cellular function through modulating the generation of lipid 2nd messengers, membrane physical properties, and cellular bioenergetics. Here, we demonstrate that mice null for calcium-independent phospholipase A(2)γ (iPLA(2)γ(-/-)) are completely resistant to high fat diet-induced weight gain, adipocyte hypertrophy, hyperinsulinemia, and insulin resistance, which occur in iPLA(2)γ(+/+) mice after high fat feeding. Notably, iPLA(2)γ(-/-) mice were lean, demonstrated abdominal lipodystrophy, and remained insulin-sensitive despite having a marked impairment in glucose-stimulated insulin secretion after high fat feeding. Respirometry of adipocyte explants from iPLA(2)γ(-/-) mice identified increased rates of oxidation of multiple different substrates in comparison with adipocyte explants from wild-type littermates. Shotgun lipidomics of adipose tissue from wild-type mice demonstrated the anticipated 2-fold increase in triglyceride content after high fat feeding. In sharp contrast, the adipocyte triglyceride content was identical in iPLA(2)γ(-/-) mice fed either a standard diet or a high fat diet. Respirometry of skeletal muscle mitochondria from iPLA(2)γ(-/-) mice demonstrated marked decreases in state 3 respiration using multiple substrates whose metabolism was uncoupled from ATP production. Shotgun lipidomics of skeletal muscle revealed a decreased content of cardiolipin with an altered molecular species composition thereby identifying the mechanism underlying mitochondrial uncoupling in the iPLA(2)γ(-/-) mouse. Collectively, these results identify iPLA(2)γ as an obligatory upstream enzyme that is necessary for efficient electron transport chain coupling and energy production through its participation in the alterations of cellular bioenergetics that promote the development of the metabolic syndrome.
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Affiliation(s)
- David J Mancuso
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Sharma J, Turk J, McHowat J. Endothelial cell prostaglandin I(2) and platelet-activating factor production are markedly attenuated in the calcium-independent phospholipase A(2)beta knockout mouse. Biochemistry 2010; 49:5473-81. [PMID: 20521843 DOI: 10.1021/bi100752u] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Damage and activation of lung endothelium can lead to interstitial edema, infiltration of inflammatory cells into the interstitium and airways, and production of inflammatory metabolites, all of which propagate airway inflammation in a variety of diseases. We have previously determined that stimulation of human microvascular endothelial cells from lung (HMVEC-L) results in activation of a calcium-independent phospholipase A(2) (iPLA(2)), and this leads to arachidonic acid release and production of prostaglandin I(2) (PGI(2)) and platelet-activating factor (PAF). We stimulated lung endothelial cells isolated from iPLA(2)beta-knockout (KO) and wild type (WT) mice with thrombin and tryptase to determine the role of iPLA(2)beta in endothelial cell membrane phospholipid hydrolysis. Thrombin or tryptase stimulation of WT lung endothelial cells resulted in increased arachidonic acid release and production of PGI(2) and PAF. Arachidonic acid release and PGI(2) production by stimulated iPLA(2)beta-KO endothelial cells were significantly reduced compared to WT. Measured PLA(2) activity and PGI(2) production by iPLA(2)beta-KO cells were suppressed by pretreatment with (R)-bromoenol lactone (R-BEL), which is a selective inhibitor of iPLA2gamma. In contrast to the increase in PAF production induced by stimulation of WT endothelial cells, none was observed for KO cells, and this suggests that endothelial PAF production is entirely dependent on iPLA(2)beta activity. Because inflammatory cell recruitment involves the interaction of endothelial cell PAF with PAF receptors on circulating cells, these data suggest that iPLA(2)beta may be a suitable therapeutic target for the treatment of inflammatory lung diseases.
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Affiliation(s)
- Janhavi Sharma
- Department of Pathology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
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