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Jabůrek M, Průchová P, Holendová B, Galkin A, Ježek P. Antioxidant Synergy of Mitochondrial Phospholipase PNPLA8/iPLA2γ with Fatty Acid-Conducting SLC25 Gene Family Transporters. Antioxidants (Basel) 2021; 10:antiox10050678. [PMID: 33926059 PMCID: PMC8146845 DOI: 10.3390/antiox10050678] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/13/2021] [Accepted: 04/22/2021] [Indexed: 02/07/2023] Open
Abstract
Patatin-like phospholipase domain-containing protein PNPLA8, also termed Ca2+-independent phospholipase A2γ (iPLA2γ), is addressed to the mitochondrial matrix (or peroxisomes), where it may manifest its unique activity to cleave phospholipid side-chains from both sn-1 and sn-2 positions, consequently releasing either saturated or unsaturated fatty acids (FAs), including oxidized FAs. Moreover, iPLA2γ is directly stimulated by H2O2 and, hence, is activated by redox signaling or oxidative stress. This redox activation permits the antioxidant synergy with mitochondrial uncoupling proteins (UCPs) or other SLC25 mitochondrial carrier family members by FA-mediated protonophoretic activity, termed mild uncoupling, that leads to diminishing of mitochondrial superoxide formation. This mechanism allows for the maintenance of the steady-state redox status of the cell. Besides the antioxidant role, we review the relations of iPLA2γ to lipid peroxidation since iPLA2γ is alternatively activated by cardiolipin hydroperoxides and hypothetically by structural alterations of lipid bilayer due to lipid peroxidation. Other iPLA2γ roles include the remodeling of mitochondrial (or peroxisomal) membranes and the generation of specific lipid second messengers. Thus, for example, during FA β-oxidation in pancreatic β-cells, H2O2-activated iPLA2γ supplies the GPR40 metabotropic FA receptor to amplify FA-stimulated insulin secretion. Cytoprotective roles of iPLA2γ in the heart and brain are also discussed.
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Affiliation(s)
- Martin Jabůrek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1084, 14220 Prague, Czech Republic; (P.P.); (B.H.); (P.J.)
- Correspondence: ; Tel.: +420-296442789
| | - Pavla Průchová
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1084, 14220 Prague, Czech Republic; (P.P.); (B.H.); (P.J.)
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1084, 14220 Prague, Czech Republic; (P.P.); (B.H.); (P.J.)
| | - Alexander Galkin
- Department of Pediatrics, Division of Neonatology, Columbia University William Black Building, New York, NY 10032, USA;
| | - Petr Ježek
- Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences, Vídeňská 1084, 14220 Prague, Czech Republic; (P.P.); (B.H.); (P.J.)
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tert-Butyl Hydroperoxide (tBHP)-Induced Lipid Peroxidation and Embryonic Defects Resemble Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency in C. elegans. Int J Mol Sci 2020; 21:ijms21228688. [PMID: 33217954 PMCID: PMC7698637 DOI: 10.3390/ijms21228688] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 11/17/2022] Open
Abstract
G6PD is required for embryonic development in animals, as severe G6PD deficiency is lethal to mice, zebrafish and nematode. Lipid peroxidation is linked to membrane-associated embryonic defects in Caenorhabditis elegans (C. elegans). However, the direct link between lipid peroxidation and embryonic lethality has not been established. The aim of this study was to delineate the role of lipid peroxidation in gspd-1-knockdown (ortholog of g6pd) C. elegans during reproduction. tert-butyl hydroperoxide (tBHP) was used as an exogenous inducer. Short-term tBHP administration reduced brood size and enhanced germ cell death in C. elegans. The altered phenotypes caused by tBHP resembled GSPD-1 deficiency in C. elegans. Mechanistically, tBHP-induced malondialdehyde (MDA) production and stimulated calcium-independent phospholipase A2 (iPLA) activity, leading to disturbed oogenesis and embryogenesis. The current study provides strong evidence to support the notion that enhanced lipid peroxidation in G6PD deficiency promotes death of germ cells and impairs embryogenesis in C. elegans.
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Guo YP, Tang BS, Liu HL, Huang JJ, Xu Q, Sun QY, Yan XX, Guo JF. Impaired iPLA 2β activity affects iron uptake and storage without iron accumulation: An in vitro study excluding decreased iPLA 2β activity as the cause of iron deposition in PLAN. Brain Res 2019; 1712:25-33. [PMID: 30707893 DOI: 10.1016/j.brainres.2019.01.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/13/2019] [Accepted: 01/27/2019] [Indexed: 01/12/2023]
Abstract
PLA2G6-associated neurodegeneration (PLAN, NBIA2) is the second most common type of neurodegeneration with brain iron accumulation (NBIA), caused by recessive mutations of PLA2G6 gene, which encodes Ca2+-independent phospholipase A2β (iPLA2β). In most PLAN cases, decreased iPLA2β activity and iron deposition was observed meanwhile, and researchers also identified a PLA2G6 mutation family without iron deposition shown by MRI images. This brought us the question of whether decreased iPLA2β activity was the cause of iron deposition in PLAN. In this study, we used S-BEL as the antagonist of iPLA2β to block its activity and used SH-SY5Y cells as the expression system. We incubated SH-SY5Y cells with different concentrations of S-BEL. The results showed that decreased iPLA2β activity led no obvious iron accumulation, while changes of cells state and activation of apoptosis were observed. To further investigate the cause of unchanged iron level, we examined the cellular iron regulatory proteins involved in iron uptake, storage and export. The results were as follows: TfR1 (iron uptake protein) expression was decreased, the expression of ferritin heavy chain and light chain (iron storage protein) was increased. There was no alteration of the expression of DMT1 (iron uptake protein) and FPN1 (iron export protein). Under the condition of decreased iPLA2β activity, there was no obvious iron accumulation but iron uptake activity decreased and iron storage activity increased. Therefore, we speculate that the decreased iPLA2β activity may not be the main reason for iron deposition in PLAN.
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Affiliation(s)
- Yu-Pei Guo
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Bei-Sha Tang
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Center for Medical Genetics, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Hong-Li Liu
- Center for Brain Disorders Research, Capital Medical University and Beijing Institute of Brain Disorders, Beijing 100069, People's Republic of China; Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Juan-Juan Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Qian Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Qi-Ying Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Xin-Xiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China
| | - Ji-Feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China; National Clinical Research Center for Geriatric Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China; Center for Medical Genetics, Central South University, Changsha 410008, Hunan, People's Republic of China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha 410008, Hunan, People's Republic of China.
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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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Li Z, Zhang J, Sun H. Increased plasma levels of phospholipid in Parkinson’s disease with mild cognitive impairment. J Clin Neurosci 2015; 22:1268-71. [DOI: 10.1016/j.jocn.2015.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 01/18/2015] [Accepted: 02/03/2015] [Indexed: 12/23/2022]
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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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Gualda EJ, Simão D, Pinto C, Alves PM, Brito C. Imaging of human differentiated 3D neural aggregates using light sheet fluorescence microscopy. Front Cell Neurosci 2014; 8:221. [PMID: 25161607 PMCID: PMC4123789 DOI: 10.3389/fncel.2014.00221] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/19/2014] [Indexed: 01/02/2023] Open
Abstract
The development of three dimensional (3D) cell cultures represents a big step for the better understanding of cell behavior and disease in a more natural like environment, providing not only single but multiple cell type interactions in a complex 3D matrix, highly resembling physiological conditions. Light sheet fluorescence microscopy (LSFM) is becoming an excellent tool for fast imaging of such 3D biological structures. We demonstrate the potential of this technique for the imaging of human differentiated 3D neural aggregates in fixed and live samples, namely calcium imaging and cell death processes, showing the power of imaging modality compared with traditional microscopy. The combination of light sheet microscopy and 3D neural cultures will open the door to more challenging experiments involving drug testing at large scale as well as a better understanding of relevant biological processes in a more realistic environment.
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Affiliation(s)
- Emilio J. Gualda
- Cell Imaging Unit, Instituto Gulbenkian de CiênciaOeiras, Portugal
| | - Daniel Simão
- iBET - Instituto de Biologia Experimental e TecnológicaOeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
| | - Catarina Pinto
- iBET - Instituto de Biologia Experimental e TecnológicaOeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
| | - Paula M. Alves
- iBET - Instituto de Biologia Experimental e TecnológicaOeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
| | - Catarina Brito
- iBET - Instituto de Biologia Experimental e TecnológicaOeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de LisboaOeiras, Portugal
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Maintenance of synaptic stability requires calcium-independent phospholipase A₂ activity. Neural Plast 2012; 2012:569149. [PMID: 22685677 PMCID: PMC3364014 DOI: 10.1155/2012/569149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/03/2012] [Accepted: 02/07/2012] [Indexed: 12/31/2022] Open
Abstract
Phospholipases A₂ (PLA₂s) represent one of the largest groups of lipid-modifying enzymes. Over the years, significant advances have been made in understanding their potential physiological and pathological functions. Depending on their calcium requirement for activation, PLA₂s are classified into calcium dependent and independent. This paper mainly focuses on brain calcium-independent PLA₂ (iPLA₂) and on the mechanisms by which they influence neuronal function and regulate synaptic plasticity. Particular attention will be given to the iPLA₂γ isoform and its role in the regulation of synaptic glutamate receptors. In particular, the paper discusses the possibility that brain iPLA₂γ deficiencies could destabilise normal synaptic operation and might contribute to the aetiology of some brain disorders. In this line, the paper presents new data indicating that iPLA₂γ deficiencies accentuate AMPA receptor destabilization and tau phosphorylation, which suggests that this iPLA₂ isoform should be considered as a potential target for the treatment of Tau-related disorders.
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Zhang X, Bull RJ, Fisher J, Cotruvo JA, Cummings BS. The synergistic effect of sodium chlorite and bromochloroacetic acid on BrO3(-)-induced renal cell death. Toxicology 2011; 289:151-9. [PMID: 21864635 DOI: 10.1016/j.tox.2011.08.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/27/2011] [Accepted: 08/08/2011] [Indexed: 11/19/2022]
Abstract
Bromate (BrO(3)(-)) is a drinking water disinfection by-product (DBP) that induces renal cell death via DNA damage-dependent and -independent mechanisms. Drinking water contains other DBPs in addition to BrO(3)(-). We tested the effect of two of these, sodium chlorite (NaClO(2)) and bromochloroacetic acid (BCAA), on BrO(3)(-) cytotoxicity in normal rat kidney (NRK) cells. NaClO(2) and BCAA alone induced cytotoxicity at concentrations of over 20ppm, while BrO(3)(-) was only moderately cytotoxic at concentrations of 200ppm. Combining BrO(3)(-) with NaClO(2) or BCAA alone enhanced cytotoxicity 1.5-4 fold. Exposing cells to all three compounds induced synergistic-like increases in cytotoxicity. This effect did not correlate to increases in reactive oxygen species (ROS), even though all three compounds induced ROS formation alone. NaClO(2), but not BCAA, increased BrO(3)(-)-mediated DNA damage as measured by 8-hydroxydeoxyguanosine (8-OHdG) staining. In addition, NaClO(2), but not BCAA, decreased BrO(3)(-)-induced G2/M cell cycle arrest. Both compounds increased apoptosis in the presence of BrO(3)(-) as assessed by annexin V, PI, and DAPI staining. This is in contrast to BrO(3)(-) treatment alone, which induced necrosis. Immunoblot analysis showed that both NaClO(2) and BCAA increased p38 activation; however, consistent with 8-OHdG staining, only NaClO(2) increased BrO(3)(-)-induced histone H2AX phosphorylation, a marker of DNA damage. In contrast, BCAA, but not NaClO(2), increased BrO(3)(-)-induced phosphorylation of p53. These data support the novel finding that mixtures of DBPs increase BrO(3)(-)-induced renal cell death by DNA-dependent and -independent mechanisms, and could alter how the risk of these DBPs towards humans is assessed.
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Affiliation(s)
- Xiaoling Zhang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, United States
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AL-Shawaf E, Tumova S, Naylor J, Majeed Y, Li J, Beech DJ. GVI phospholipase A2 role in the stimulatory effect of sphingosine-1-phosphate on TRPC5 cationic channels. Cell Calcium 2011; 50:343-50. [PMID: 21742378 PMCID: PMC3195672 DOI: 10.1016/j.ceca.2011.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 11/16/2022]
Abstract
The Transient Receptor Potential Canonical 5 (TRPC5) protein forms calcium-permeable cationic channels that are stimulated by G protein-coupled receptor agonists. The signaling pathways of such agonist effects are poorly understood. Here we investigated the potential for involvement of lysophosphatidylcholine (LPC) and arachidonic acid generated by group 6 (GVI) phospholipase A2 (PLA2) enzymes, focusing on stimulation of TRPC5 by sphingosine-1-phosphate (S1P) which acts via a pertussis toxin-sensitive (Gi/o protein) pathway without Ca2+-release. Experiments were on HEK 293 cells containing conditional expression of human TRPC5. Channel activity was recorded using an intracellular calcium indicator or whole-cell patch-clamp and PLA2 activity was detected using 3H-arachidonic acid. S1P stimulated PLA2 and TRPC5 activities. Both effects were suppressed by the GVI PLA2 inhibitor bromoenol lactone. Knock-down of GVI PLA2 by RNA interference suppressed channel activity evoked by S1P whereas activity evoked by the direct channel stimulator LPC was unaffected. Arachidonic acid did not stimulate the channels. Prior exposure of channels to LPC but not arachidonic acid suppressed channel activity evoked by S1P but not gadolinium, a putative direct stimulator of the channels. The data suggest roles of LPC and GVI PLA2 in S1P-evoked TRPC5 activity.
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Affiliation(s)
- Eman AL-Shawaf
- Multidisciplinary Cardiovascular Research Centre and the Institute of Membrane & Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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Polster B, Crosier M, Lindsay S, Hayflick S. Expression of PLA2G6 in human fetal development: Implications for infantile neuroaxonal dystrophy. Brain Res Bull 2010; 83:374-9. [PMID: 20813170 PMCID: PMC2975838 DOI: 10.1016/j.brainresbull.2010.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/17/2010] [Accepted: 08/24/2010] [Indexed: 12/22/2022]
Abstract
Mutations in PLA2G6, which encodes calcium-independent phospholipase A(2) group VIA (iPLA2-VIA), underlie the autosomal recessive disorder infantile neuroaxonal dystrophy (INAD). INAD typically presents in the first year of life, and leads to optic atrophy and psychomotor regression. We have examined PLA2G6 expression in early human embryonic development by in situ hybridization. At Carnegie Stage (CS) 19 (approximately 7 post-conception weeks [PCW]), strong expression is evident in the ventricular zone (VZ) of midbrain and forebrain suggestive of expression in neural stem and progenitor cells. At CS23 (8PCW) expression is also detectable in the VZ of the hindbrain and the subventricular zone (SVZ) of the developing neocortex, ganglionic eminences and diencephalon. By 9PCW strong expression in the post-mitotic cells of the cortical plate can be seen in the developing neocortex. In the eye, expression is seen in the lens and retina at all stages examined. PLA2G6 expression is also evident in the alar plate of the spinal cord, dorsal root ganglia, the retina and lens in the eye and several non-neuronal tissues, including developing bones, lung, kidney and gut. These findings suggest a role for PLA2G6 in neuronal proliferation throughout the developing brain and in maturing neurons in the cortical plate and hindbrain. Although widespread PLA2G6 expression is detected in neuronal tissues, the pattern shows dynamic changes with time and indicates that INAD pathogenesis may begin prior to birth.
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Affiliation(s)
- Brenda Polster
- Molecular and Medical Genetics, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, United States.
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Zhang X, De Silva D, Sun B, Fisher J, Bull RJ, Cotruvo JA, Cummings BS. Cellular and molecular mechanisms of bromate-induced cytotoxicity in human and rat kidney cells. Toxicology 2010; 269:13-23. [PMID: 20067818 DOI: 10.1016/j.tox.2010.01.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/22/2009] [Accepted: 01/05/2010] [Indexed: 11/30/2022]
Abstract
The mechanisms of bromate (BrO(3)(-))-induced toxicity in Normal Rat Kidney (NRK) and human embryonic kidney 293 (HEK293) cells were investigated. BrO(3)(-) (added as KBrO(3)) induced concentration-dependent decreases in 3-(4, dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) staining after 48 h. BrO(3)(-)-induced necrosis based on tandem increases in annexin V and PI staining. Cell cycle analysis demonstrated that BrO(3)(-) also induced G2/M arrest and nuclear fragmentation, prior to alterations in MTT staining or annexin V and PI staining. Immunoblot analysis demonstrated that the G2/M arrest correlated to induction of phosphorylated (p)-p53, p21, cyclin B1 and p-cdc2. Further, BrO(3)(-) induced time-dependent increases in the activity of the mitogen activated protein kinases p38 and ERK1/2. Treatment of cells with the p38 inhibitor SB202190, but not the ERK1/2 inhibitor PD98059, partially reversed BrO(3)(-)-induced G2/M arrest and decreased BrO(3)(-)-induced p-p53, p21 and cyclin B1 expression. In addition, BrO(3)(-) treatment induced reactive oxygen species (ROS) based on increases in CM-H(2)DCFDA fluorescence. The antioxidant ascorbic acid inhibited BrO(3)(-)-induced p38 activation, G2/M arrest, p-p53, p21 and cyclin B1 expression; however, ascorbic acid had no effect on BrO(3)(-)-induced formation of 8-OHdG, a marker of DNA oxidative damage, whose increases preceded cell death by 24h. These data suggest that ROS mediated MAPK activation is involved in the molecular mechanisms of BrO(3)(-)-induced cell cycle arrest, which occurs independently of 8-OH-dG production. The similar mode of action in both NRK and HEK293 cells suggests that the mechanisms of BrO(3)(-)-induced renal cell death are model-independent.
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Affiliation(s)
- Xiaoling Zhang
- Department of Pharmaceutical and Biomedical Sciences, 336 Pharmacy South, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
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Sun GY, Shelat PB, Jensen MB, He Y, Sun AY, Simonyi A. Phospholipases A2 and inflammatory responses in the central nervous system. Neuromolecular Med 2009; 12:133-48. [PMID: 19855947 DOI: 10.1007/s12017-009-8092-z] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 09/25/2009] [Indexed: 12/21/2022]
Abstract
Phospholipases A2 (PLA2s) belong to a superfamily of enzymes responsible for hydrolyzing the sn-2 fatty acids of membrane phospholipids. These enzymes are known to play multiple roles for maintenance of membrane phospholipid homeostasis and for production of a variety of lipid mediators. Over 20 different types of PLA2s are present in the mammalian cells, and in snake and bee venom. Despite their common function in hydrolyzing fatty acids of phospholipids, they are diversely encoded by a number of genes and express proteins that are regulated by different mechanisms. Recent studies have focused on the group IV calcium-dependent cytosolic cPLA2, the group VI calcium-independent iPLA2, and the group II small molecule secretory sPLA2. In the central nervous system (CNS), these PLA2s are distributed among neurons and glial cells. Although the physiological role of these PLA2s in regulating neural cell function has not yet been clearly elucidated, there is increasing evidence for their involvement in receptor signaling and transcriptional pathways that link oxidative events to inflammatory responses that underline many neurodegenerative diseases. Recent studies also reveal an important role of cPLA2 in modulating neuronal excitatory functions, sPLA2 in the inflammatory responses, and iPLA2 with childhood neurologic disorders associated with brain iron accumulation. The goal for this review is to better understand the structure and function of these PLA2s and to highlight specific types of PLA2s and their cross-talk mechanisms in these inflammatory responses under physiological and pathological conditions in the CNS.
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Affiliation(s)
- Grace Y Sun
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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Rosa AO, Rapoport SI. Intracellular- and extracellular-derived Ca(2+) influence phospholipase A(2)-mediated fatty acid release from brain phospholipids. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:697-705. [PMID: 19327408 DOI: 10.1016/j.bbalip.2009.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 03/01/2009] [Accepted: 03/11/2009] [Indexed: 02/01/2023]
Abstract
Docosahexaenoic acid (DHA) and arachidonic acid (AA) are found in high concentrations in brain cell membranes and are important for brain function and structure. Studies suggest that AA and DHA are hydrolyzed selectively from the sn-2 position of synaptic membrane phospholipids by Ca(2+)-dependent cytosolic phospholipase A(2) (cPLA(2)) and Ca(2+)-independent phospholipase A(2) (iPLA(2)), respectively, resulting in increased levels of the unesterified fatty acids and lysophospholipids. Cell studies also suggest that AA and DHA release depend on increased concentrations of Ca(2+), even though iPLA(2) has been thought to be Ca(2+)-independent. The source of Ca(2+) for activation of cPLA(2) is largely extracellular, whereas Ca(2+) released from the endoplasmic reticulum can activate iPLA(2) by a number of mechanisms. This review focuses on the role of Ca(2+) in modulating cPLA(2) and iPLA(2) activities in different conditions. Furthermore, a model is suggested in which neurotransmitters regulate the activity of these enzymes and thus the balanced and localized release of AA and DHA from phospholipid in the brain, depending on the primary source of the Ca(2+) signal.
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Affiliation(s)
- Angelo O Rosa
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Abstract
The phospholipase A(2) (PLA(2)) superfamily consists of many different groups of enzymes that catalyze the hydrolysis of the sn-2 ester bond in a variety of different phospholipids. The products of this reaction, a free fatty acid, and lysophospholipid have many different important physiological roles. There are five main types of PLA(2): the secreted sPLA(2)'s, the cytosolic cPLA(2)'s, the Ca(2+)independent iPLA(2)'s, the PAF acetylhydrolases, and the lysosomal PLA(2)'s. This review focuses on the superfamily of PLA(2) enzymes, and then uses three specific examples of these enzymes to examine the differing biochemistry of the three main types of these enzymes. These three examples are the GIA cobra venom PLA(2), the GIVA cytosolic cPLA(2), and the GVIA Ca(2+)-independent iPLA(2).
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Affiliation(s)
- John E Burke
- Department of Chemistry and Biochemistry, School of Medicine, University of California, La Jolla, San Diego, CA 92093-0601, USA
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16
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Peterson B, Stovall K, Monian P, Franklin JL, Cummings BS. Alterations in phospholipid and fatty acid lipid profiles in primary neocortical cells during oxidant-induced cell injury. Chem Biol Interact 2008; 174:163-76. [PMID: 18602625 DOI: 10.1016/j.cbi.2008.05.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 05/19/2008] [Accepted: 05/22/2008] [Indexed: 10/22/2022]
Abstract
Specific phospholipids and fatty acids altered during oxidant-induced neuronal cell injury were determined using electrospray ionization mass spectrometry (ESI-MS) and ion trapping. The oxidants hydrogen peroxide (H(2)O(2), 0-1000 microM) and tert-butylhydroperoxide (TBHP, 0-400 microM) induced time- and concentration-dependent increases in reactive oxygen species in primary cultures of mouse neocortical cells as determined by 2',7'-dichlorofluorescein diacetate staining and thiobarbituric acid formation. ESI-MS analysis of 26 m/z values, representing 42 different phospholipids, demonstrated that H(2)O(2) and TBHP increased the abundance of phospholipids containing polyunsaturated fatty acids, but had minimal affect on those containing mono- or di-unsaturated fatty acids. These increases correlated to time-dependent increase in 16:1-20:4, 16:0-20:4, 18:1-20:4 and 18:0-20:4 phosphatidylcholine. Oxidant exposure also increased mystric (14:0), palmitic (16:0), and stearic (18:0) acid twofold, oleic acid (18:1) two- to threefold, and arachidonic acid (20:4) fourfold, compared to controls. Increases in arachidonic acid levels occurred prior to increases in the phospholipids, but after increases in ROS, and correlated to increases in oxidized arachidonic acid species, specifically [20:4-OOH]-H(2)O-, 20:4-OH-, and Tri-OH-20:4-arachidonic acid. Treatment of cells with methyl arachidonyl flourophosphonate an inhibitor of Group IV and VI PLA(2), decreased oxidant-induced arachidonic acid release, while bromoenol lactone, an inhibitor of Group VI PLA(2), did not. Collectively, these data identify phospholipids and fatty acids altered during oxidant treatment of neurons and suggest differential roles for Group IV and VI PLA(2) in oxidant-induced neural cell injury.
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Affiliation(s)
- Brianna Peterson
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia, Athens, GA 30602-2352, United States
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