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Di Meo C, Tortolani D, Standoli S, Ciaramellano F, Angelucci BC, Tisi A, Kadhim S, Hsu E, Rapino C, Maccarrone M. Cannabinol modulates the endocannabinoid system and shows TRPV1-mediated anti-inflammatory properties in human keratinocytes. Biofactors 2024. [PMID: 39275884 DOI: 10.1002/biof.2122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 08/27/2024] [Indexed: 09/16/2024]
Abstract
Cannabinol (CBN) is a secondary metabolite of cannabis whose beneficial activity on inflammatory diseases of human skin has attracted increasing attention. Here, we sought to investigate the possible modulation by CBN of the major elements of the endocannabinoid system (ECS), in both normal and lipopolysaccharide-inflamed human keratinocytes (HaCaT cells). CBN was found to increase the expression of cannabinoid receptor 1 (CB1) at gene level and that of vanilloid receptor 1 (TRPV1) at protein level, as well as their functional activity. In addition, CBN modulated the metabolism of anandamide (AEA) and 2-arachidonoylglicerol (2-AG), by increasing the activities of N-acyl phosphatidylethanolamines-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH)-the biosynthetic and degradative enzyme of AEA-and that of monoacylglycerol lipase (MAGL), the hydrolytic enzyme of 2-AG. CBN also affected keratinocyte inflammation by reducing the release of pro-inflammatory interleukin (IL)-8, IL-12, and IL-31 and increasing the release of anti-inflammatory IL-10. Of note, the release of IL-31 was mediated by TRPV1. Finally, the mitogen-activated protein kinases (MAPK) signaling pathway was investigated in inflamed keratinocytes, demonstrating a specific modulation of glycogen synthase kinase 3β (GSK3β) upon treatment with CBN, in the presence or not of distinct ECS-directed drugs. Overall, these results demonstrate that CBN modulates distinct ECS elements and exerts anti-inflammatory effects-remarkably via TRPV1-in human keratinocytes, thus holding potential for both therapeutic and cosmetic purposes.
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Affiliation(s)
- Camilla Di Meo
- Department of Veterinary Medicine, University of Teramo, Teramo, Italy
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Daniel Tortolani
- Department of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - Sara Standoli
- Department of Veterinary Medicine, University of Teramo, Teramo, Italy
| | | | | | - Annamaria Tisi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Salam Kadhim
- InMed Pharmaceuticals Inc., Vancouver, BC, Canada
| | - Eric Hsu
- InMed Pharmaceuticals Inc., Vancouver, BC, Canada
| | - Cinzia Rapino
- Department of Veterinary Medicine, University of Teramo, Teramo, Italy
| | - Mauro Maccarrone
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy
- European Center for Brain Research (CERC), Santa Lucia Foundation IRCCS, Rome, Italy
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2
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Activity and Crystal Structure of the Adherent-Invasive Escherichia coli Tle3/Tli3 T6SS Effector/Immunity Complex Determined Using an AlphaFold2 Predicted Model. Int J Mol Sci 2023; 24:ijms24021740. [PMID: 36675258 PMCID: PMC9860674 DOI: 10.3390/ijms24021740] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
The type VI secretion system (T6SS) delivers enzymatic effectors into target cells to destroy them. Cells of the same strain protect themselves against effectors with immunity proteins that specifically inhibit effectors. Here, we report the identification and characterization of a Tle3 phospholipase effector and its cognate immunity protein Tli3-an outer membrane lipoprotein from adherent-invasive Escherichia coli (AIEC). Enzymatic assays demonstrate that purified Tle3AIEC has a phospholipase A1, and not A2, activity and that its toxicity is neutralized by the cognate immunity protein Tli3AIEC. Tli3AIEC binds Tle3 in a 1:1 stoichiometric ratio. Tle3AIEC, Tli3AIEC and the Tle3AIEC-Tli3AIEC complex were purified and subjected to crystallization. The Tle3AIEC-Tli3AIEC complex structure could not be solved by SeMet phasing, but only by molecular replacement when using an AlphaFold2 prediction model. Tle3AIEC exhibits an α/β-hydrolase fold decorated by two protruding segments, including a N-terminus loop. Tli3AIEC displays a new fold of three stacked β-sheets and a protruding loop that inserts in Tle3AIECcatalytic crevice. We showed, experimentally, that Tle3AIEC interacts with the VgrG AIEC cargo protein and AlphaFold2 prediction of the VgrGAIEC-Tle3AIEC complex reveals a strong interaction between the VgrGAIEC C-terminus adaptor and Tle3AIEC N-terminal loop.
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Effects of Rare Phytocannabinoids on the Endocannabinoid System of Human Keratinocytes. Int J Mol Sci 2022; 23:ijms23105430. [PMID: 35628241 PMCID: PMC9145865 DOI: 10.3390/ijms23105430] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/06/2022] [Accepted: 05/11/2022] [Indexed: 02/06/2023] Open
Abstract
The decriminalization and legalization of cannabis has paved the way for investigations into the potential of the use of phytocannabinoids (pCBs) as natural therapeutics for the treatment of human diseases. This growing interest has recently focused on rare (less abundant) pCBs that are non-psychotropic compounds, such as cannabigerol (CBG), cannabichromene (CBC), Δ9-tetrahydrocannabivarin (THCV) and cannabigerolic acid (CBGA). Notably, pCBs can act via the endocannabinoid system (ECS), which is involved in the regulation of key pathophysiological processes, and also in the skin. In this study, we used human keratinocytes (HaCaT cells) as an in vitro model that expresses all major ECS elements in order to systematically investigate the effects of CBG, CBC, THCV and CBGA. To this end, we analyzed the gene and protein expression of ECS components (receptors: CB1, CB2, GPR55, TRPV1 and PPARα/γ/δ; enzymes: NAPE-PLD, FAAH, DAGLα/β and MAGL) using qRT-PCR and Western blotting, along with assessments of their functionality using radioligand binding and activity assays. In addition, we quantified the content of endocannabinoid(-like) compounds (AEA, 2-AG, PEA, etc.) using UHPLC-MS/MS. Our results demonstrated that rare pCBs modulate the gene and protein expression of distinct ECS elements differently, as well as the content of endocannabinoid(-like) compounds. Notably, they all increased CB1/2 binding, TRPV1 channel stimulation and FAAH and MAGL catalytic activity. These unprecedented observations should be considered when exploring the therapeutic potential of cannabis extracts for the treatment of human skin diseases.
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4
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High-throughput optical assays for sensing serine hydrolases in living systems and their applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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5
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Zarrow JE, Tian J, Dutter B, Kim K, Doran AC, Sulikowski GA, Davies SS. Selective measurement of NAPE-PLD activity via a PLA 1/2-resistant fluorogenic N-acyl-phosphatidylethanolamine analog. J Lipid Res 2022; 63:100156. [PMID: 34843683 PMCID: PMC8953660 DOI: 10.1016/j.jlr.2021.100156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 12/24/2022] Open
Abstract
N-acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a zinc metallohydrolase enzyme that converts NAPEs to bioactive N-acyl-ethanolamides. Altered NAPE-PLD activity may contribute to pathogenesis of obesity, diabetes, atherosclerosis, and neurological diseases. Selective measurement of NAPE-PLD activity is challenging, however, because of alternative phospholipase pathways for NAPE hydrolysis. Previous methods to measure NAPE-PLD activity involved addition of exogenous NAPE followed by TLC or LC/MS/MS, which are time and resource intensive. Recently, NAPE-PLD activity in cells has been assayed using the fluorogenic NAPE analogs PED-A1 and PED6, but these substrates also detect the activity of serine hydrolase-type lipases PLA1 and PLA2. To create a fluorescence assay that selectively measured cellular NAPE-PLD activity, we synthesized an analog of PED-A1 (flame-NAPE) where the sn-1 ester bond was replaced with an N-methyl amide to create resistance to PLA1 hydrolysis. Recombinant NAPE-PLD produced fluorescence when incubated with either PED-A1 or flame-NAPE, whereas PLA1 only produced fluorescence when incubated with PED-A1. Furthermore, fluorescence in HepG2 cells using PED-A1 could be partially blocked by either biothionol (a selective NAPE-PLD inhibitor) or tetrahydrolipstatin (an inhibitor of a broad spectrum of serine hydrolase-type lipases). In contrast, fluorescence assayed in HepG2 cells using flame-NAPE could only be blocked by biothionol. In multiple cell types, the phospholipase activity detected using flame-NAPE was significantly more sensitive to biothionol inhibition than that detected using PED-A1. Thus, using flame-NAPE to measure phospholipase activity provides a rapid and selective method to measure NAPE-PLD activity in cells and tissues.
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Affiliation(s)
- Jonah E Zarrow
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jianhua Tian
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - Brendan Dutter
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Amanda C Doran
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gary A Sulikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Sean S Davies
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA.
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Kuge H, Miyamoto I, Yagyu KI, Honke K. PLRP2 selectively localizes synaptic membrane proteins via acyl-chain remodeling of phospholipids. J Lipid Res 2020; 61:1747-1763. [PMID: 32963038 PMCID: PMC7707162 DOI: 10.1194/jlr.ra120001087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The plasma membrane of neurons consists of distinct domains, each of which carries specialized functions and a characteristic set of membrane proteins. While this compartmentalized membrane organization is essential for neuronal functions, it remains controversial how neurons establish these domains on the laterally fluid membrane. Here, using immunostaining, lipid-MS analysis and gene ablation with the CRISPR/Cas9 system, we report that the pancreatic lipase-related protein 2 (PLRP2), a phospholipase A1 (PLA1), is a key organizer of membrane protein localization at the neurite tips of PC12 cells. PLRP2 produced local distribution of 1-oleoyl-2-palmitoyl-PC at these sites through acyl-chain remodeling of membrane phospholipids. The resulting lipid domain assembled the syntaxin 4 (Stx4) protein within itself by selectively interacting with the transmembrane domain of Stx4. The localized Stx4, in turn, facilitated the fusion of transport vesicles that contained the dopamine transporter with the domain of the plasma membrane, which led to the localized distribution of the transporter to that domain. These results revealed the pivotal roles of PLA1, specifically PLRP2, in the formation of functional domains in the plasma membrane of neurons. In addition, our results suggest a mode of membrane organization in which the local acyl-chain remodeling of membrane phospholipids controls the selective localization of membrane proteins by regulating both lipid-protein interactions and the fusion of transport vesicles to the lipid domain.
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Affiliation(s)
- Hideaki Kuge
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan.
| | - Izumi Miyamoto
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan
| | - Ken-Ichi Yagyu
- Science Research Center, Kochi University Medical School, Nankoku, Kochi, Japan
| | - Koichi Honke
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan.
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7
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Still KB, Slagboom J, Kidwai S, Xie C, Zhao Y, Eisses B, Jiang Z, Vonk FJ, Somsen GW, Casewell NR, Kool J. Development of high-throughput screening assays for profiling snake venom phospholipase A2 activity after chromatographic fractionation. Toxicon 2020; 184:28-38. [DOI: 10.1016/j.toxicon.2020.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 10/24/2022]
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8
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Silva Balbin Villaverde AI, Ogle RA, Lewis P, Carbone V, Velkov T, Netherton JK, Baker MA. Sialylation of Asparagine 612 Inhibits Aconitase Activity during Mouse Sperm Capacitation; a Possible Mechanism for the Switch from Oxidative Phosphorylation to Glycolysis. Mol Cell Proteomics 2020; 19:1860-1875. [PMID: 32839225 DOI: 10.1074/mcp.ra120.002109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/22/2020] [Indexed: 11/06/2022] Open
Abstract
After ejaculation, mammalian spermatozoa must undergo a process known as capacitation in order to successfully fertilize the oocyte. Several post-translational modifications occur during capacitation, including sialylation, which despite being limited to a few proteins, seems to be essential for proper sperm-oocyte interaction. Regardless of its importance, to date, no single study has ever identified nor quantified which glycoproteins bearing terminal sialic acid (Sia) are altered during capacitation. Here we characterize sialylation during mouse sperm capacitation. Using tandem MS coupled with liquid chromatography (LC-MS/MS), we found 142 nonreductant peptides, with 9 of them showing potential modifications on their sialylated oligosaccharides during capacitation. As such, N-linked sialoglycopeptides from C4b-binding protein, endothelial lipase (EL), serine proteases 39 and 52, testis-expressed protein 101 and zonadhesin were reduced following capacitation. In contrast, mitochondrial aconitate hydratase (aconitase; ACO2), a TCA cycle enzyme, was the only protein to show an increase in Sia content during capacitation. Interestingly, although the loss of Sia within EL (N62) was accompanied by a reduction in its phospholipase A1 activity, a decrease in the activity of ACO2 (i.e. stereospecific isomerization of citrate to isocitrate) occurred when sialylation increased (N612). The latter was confirmed by N612D recombinant protein tagged with both His and GFP. The replacement of Sia for the negatively charged Aspartic acid in the N612D mutant caused complete loss of aconitase activity compared with the WT. Computer modeling show that N612 sits atop the catalytic site of ACO2. The introduction of Sia causes a large conformational change in the alpha helix, essentially, distorting the active site, leading to complete loss of function. These findings suggest that the switch from oxidative phosphorylation, over to glycolysis that occurs during capacitation may come about through sialylation of ACO2.
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Affiliation(s)
- Ana Izabel Silva Balbin Villaverde
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Rachel A Ogle
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Peter Lewis
- Centre for Chemical Biology and Clinical Pharmacology, Department of Biology, School of Environmental & Life Sciences, The University of Newcastle, Callaghan, Australia
| | - Vincenzo Carbone
- AgResearchGrasslands Research Centre, Palmerston North, New Zealand
| | - Tony Velkov
- Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, NSW, Australia
| | - Jacob K Netherton
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia
| | - Mark A Baker
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW, Australia.
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Flaugnatti N, Rapisarda C, Rey M, Beauvois SG, Nguyen VA, Canaan S, Durand E, Chamot‐Rooke J, Cascales E, Fronzes R, Journet L. Structural basis for loading and inhibition of a bacterial T6SS phospholipase effector by the VgrG spike. EMBO J 2020; 39:e104129. [PMID: 32350888 PMCID: PMC7265238 DOI: 10.15252/embj.2019104129] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 11/09/2022] Open
Abstract
The bacterial type VI secretion system (T6SS) is a macromolecular machine that injects effectors into prokaryotic and eukaryotic cells. The mode of action of the T6SS is similar to contractile phages: the contraction of a sheath structure pushes a tube topped by a spike into target cells. Effectors are loaded onto the spike or confined into the tube. In enteroaggregative Escherichia coli, the Tle1 phospholipase binds the C-terminal extension of the VgrG trimeric spike. Here, we purify the VgrG-Tle1 complex and show that a VgrG trimer binds three Tle1 monomers and inhibits their activity. Using covalent cross-linking coupled to high-resolution mass spectrometry, we provide information on the sites of contact and further identify the requirement for a Tle1 N-terminal secretion sequence in complex formation. Finally, we report the 2.6-Å-resolution cryo-electron microscopy tri-dimensional structure of the (VgrG)3 -(Tle1)3 complex revealing how the effector binds its cargo, and how VgrG inhibits Tle1 phospholipase activity. The inhibition of Tle1 phospholipase activity once bound to VgrG suggests that Tle1 dissociation from VgrG is required upon delivery.
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Affiliation(s)
- Nicolas Flaugnatti
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
- Present address:
Laboratory of Molecular MicrobiologyGlobal Health InstituteSchool of Life SciencesEcole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Chiara Rapisarda
- Institut Européen de Chimie et BiologieUniversity of BordeauxPessacFrance
- CNRS UMR 5234 Microbiologie Fondamentale et PathogénicitéBordeauxFrance
- Present address:
UCB PharmaSloughUK
| | - Martial Rey
- Mass Spectrometry for Biology UnitInstitut PasteurCNRS USR 2000CITECHParisFrance
| | - Solène G Beauvois
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
| | - Viet Anh Nguyen
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
| | - Stéphane Canaan
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
| | - Eric Durand
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
| | - Julia Chamot‐Rooke
- Mass Spectrometry for Biology UnitInstitut PasteurCNRS USR 2000CITECHParisFrance
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
| | - Rémi Fronzes
- Institut Européen de Chimie et BiologieUniversity of BordeauxPessacFrance
- CNRS UMR 5234 Microbiologie Fondamentale et PathogénicitéBordeauxFrance
| | - Laure Journet
- Laboratoire d'Ingénierie des Systèmes MacromoléculairesInstitut de Microbiologie de la MéditerranéeAix‐Marseille Université—CNRS UMR7255MarseilleFrance
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10
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Aggarwal G, Zarrow JE, Mashhadi Z, Flynn CR, Vinson P, Weaver CD, Davies SS. Symmetrically substituted dichlorophenes inhibit N-acyl-phosphatidylethanolamine phospholipase D. J Biol Chem 2020; 295:7289-7300. [PMID: 32284327 PMCID: PMC7247316 DOI: 10.1074/jbc.ra120.013362] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/06/2020] [Indexed: 01/09/2023] Open
Abstract
N-Acyl-phosphatidylethanolamine phospholipase D (NAPE-PLD) (EC 3.1.4.4) catalyzes the final step in the biosynthesis of N-acyl-ethanolamides. Reduced NAPE-PLD expression and activity may contribute to obesity and inflammation, but a lack of effective NAPE-PLD inhibitors has been a major obstacle to elucidating the role of NAPE-PLD and N-acyl-ethanolamide biosynthesis in these processes. The endogenous bile acid lithocholic acid (LCA) inhibits NAPE-PLD activity (with an IC50 of 68 μm), but LCA is also a highly potent ligand for TGR5 (EC50 0.52 μm). Recently, the first selective small-molecule inhibitor of NAPE-PLD, ARN19874, has been reported (having an IC50 of 34 μm). To identify more potent inhibitors of NAPE-PLD, here we used a quenched fluorescent NAPE analog, PED-A1, as a substrate for recombinant mouse Nape-pld to screen a panel of bile acids and a library of experimental compounds (the Spectrum Collection). Muricholic acids and several other bile acids inhibited Nape-pld with potency similar to that of LCA. We identified 14 potent Nape-pld inhibitors in the Spectrum Collection, with the two most potent (IC50 = ∼2 μm) being symmetrically substituted dichlorophenes, i.e. hexachlorophene and bithionol. Structure-activity relationship assays using additional substituted dichlorophenes identified key moieties needed for Nape-pld inhibition. Both hexachlorophene and bithionol exhibited significant selectivity for Nape-pld compared with nontarget lipase activities such as Streptomyces chromofuscus PLD or serum lipase. Both also effectively inhibited NAPE-PLD activity in cultured HEK293 cells. We conclude that symmetrically substituted dichlorophenes potently inhibit NAPE-PLD in cultured cells and have significant selectivity for NAPE-PLD versus other tissue-associated lipases.
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Affiliation(s)
- Geetika Aggarwal
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Jonah E Zarrow
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - Zahra Mashhadi
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232
| | - C Robb Flynn
- Division of Surgery, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Paige Vinson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232
| | - C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Sean S Davies
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232; Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232.
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11
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Dabral D, Coorssen JR. Combined targeted Omic and Functional Assays Identify Phospholipases A₂ that Regulate Docking/Priming in Calcium-Triggered Exocytosis. Cells 2019; 8:cells8040303. [PMID: 30986994 PMCID: PMC6523306 DOI: 10.3390/cells8040303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/24/2019] [Accepted: 03/28/2019] [Indexed: 12/12/2022] Open
Abstract
The fundamental molecular mechanism underlying the membrane merger steps of regulated exocytosis is highly conserved across cell types. Although involvement of Phospholipase A₂ (PLA₂) in regulated exocytosis has long been suggested, its function or that of its metabolites-a lyso-phospholipid and a free fatty acid-remain somewhat speculative. Here, using a combined bioinformatics and top-down discovery proteomics approach, coupled with lipidomic analyses, PLA₂ were found to be associated with release-ready cortical secretory vesicles (CV) that possess the minimal molecular machinery for docking, Ca2+ sensing and membrane fusion. Tightly coupling the molecular analyses with well-established quantitative fusion assays, we show for the first time that inhibition of a CV surface calcium independent intracellular PLA₂ and a luminal secretory PLA₂ significantly reduce docking/priming in the late steps of regulated exocytosis, indicating key regulatory roles in the critical step(s) preceding membrane merger.
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Affiliation(s)
- Deepti Dabral
- Molecular Physiology and Molecular Medicine Research Group, School of Medicine, Western Sydney University, Campbelltown Campus, NSW 2560, Australia.
| | - Jens R Coorssen
- Department of Health Sciences, Faculty of Applied Health Sciences and Department of Biological Sciences, Faculty of Mathematics & Science, Brock University, St. Catharines, ON L2S 3A1, Canada.
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12
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Hernández G, Villanueva-Ibarra CA, Maldonado-Vega M, López-Vanegas NC, Ruiz-Cascante CE, Calderón-Salinas JV. Participation of phospholipase-A 2 and sphingomyelinase in the molecular pathways to eryptosis induced by oxidative stress in lead-exposed workers. Toxicol Appl Pharmacol 2019; 371:12-19. [PMID: 30928402 DOI: 10.1016/j.taap.2019.03.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/08/2019] [Accepted: 03/26/2019] [Indexed: 12/19/2022]
Abstract
The increment of eryptosis in lead-exposed workers has been associated with oxidative stress, having as the main mediator [Ca2+]i. However, other molecules could participate as signals, such as PLA2 and SMase, which have been proposed to increase PGE2 and ceramides, both involved in the increment of PS externalization due to osmotic stress. To study the role of these enzymes in lead intoxication, we studied 30 lead exposed workers and 27 non-lead exposed individuals. We found, compared to non-exposed subjects, lead intoxication characterized by high blood lead concentration (median = 39.1 μg/dL), and low δ-ALAD activity (median = 348 nmol of porphobilinogen/h/mL); oxidative stress with high lipid peroxidation (median = 1.31 nmol of malondialdehyde/mL) and low TAC (median = 370 mM Trolox equivalents); a higher enzymatic activity of PLA2 (median = 518 AFU/mg) and SMase (median = 706 AFU/mg) and higher eryptosis (median = 0.92% PS externalization). Correlation and conditional probability analyses permit to associate oxidative stress and eryptosis with high PLA2 activity. However, high SMase activity was only associated with PLA2 activity. The role of these enzymes in the signal path to eryptosis induced by oxidative stress in lead-exposed workers is discussed.
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Affiliation(s)
- Gerardo Hernández
- Section Methodology of Science, Centro de Investigación y Estudios Avanzados-IPN (Cinvestav), Ciudad de México, Mexico
| | | | - María Maldonado-Vega
- Planning, Teaching and Research Department, Hospital Regional de Alta Especialidad del Bajío. León, Guanajuato, Mexico
| | | | - Claudia-Estefania Ruiz-Cascante
- Programa de Maestría y Doctorado en Ciencias Médicas, Odontológicas y de la Salud, Salud en el Trabajo, UNAM, Ciudad de México, Mexico
| | - José-Víctor Calderón-Salinas
- Biochemistry Department, Centro de Investigación y Estudios Avanzados-IPN (Cinvestav), Ciudad de México, Mexico.
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13
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Gorshkova IN, Mei X, Atkinson D. Arginine 123 of apolipoprotein A-I is essential for lecithin:cholesterol acyltransferase activity. J Lipid Res 2017; 59:348-356. [PMID: 29208698 DOI: 10.1194/jlr.m080986] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/29/2017] [Indexed: 01/10/2023] Open
Abstract
ApoA-I activates LCAT that converts lipoprotein cholesterol to cholesteryl ester (CE). Molecular dynamic simulations suggested earlier that helices 5 of two antiparallel apoA-I molecules on discoidal HDL form an amphipathic tunnel for migration of acyl chains and unesterified cholesterol to the active sites of LCAT. Our recent crystal structure of Δ(185-243)apoA-I showed the tunnel formed by helices 5/5, with two positively charged residues arginine 123 positioned at the edge of the hydrophobic tunnel. We hypothesized that these uniquely positioned residues Arg123 are poised for interaction with fatty acids produced by LCAT hydrolysis of the sn-2 chains of phosphatidylcholine, thus positioning the fatty acids for esterification to cholesterol. To test the importance of Arg123 for LCAT phospholipid hydrolysis and CE formation, we generated apoA-I[R123A] and apoA-I[R123E] mutants and made discoidal HDL with the mutants and WT apoA-I. Neither mutation of Arg123 changed the particle composition or size, or the protein conformation or stability. However, both mutations of Arg123 significantly reduced LCAT catalytic efficiency and the apparent Vmax for CE formation without affecting LCAT phospholipid hydrolysis. A control mutation, apoA-I[R131A], did not affect LCAT phospholipid hydrolysis or CE formation. These data suggest that Arg123 of apoA-I on discoidal HDL participates in LCAT-mediated cholesterol esterification.
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Affiliation(s)
- Irina N Gorshkova
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - Xiaohu Mei
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
| | - David Atkinson
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118
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14
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El Alaoui M, Soulère L, Noiriel A, Popowycz F, Khatib A, Queneau Y, Abousalham A. A continuous spectrophotometric assay that distinguishes between phospholipase A1 and A2 activities. J Lipid Res 2016; 57:1589-97. [PMID: 27194811 PMCID: PMC4959851 DOI: 10.1194/jlr.d065961] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/11/2016] [Indexed: 11/30/2022] Open
Abstract
A new spectrophotometric assay was developed to measure, continuously and specifically, phospholipase A1 (PLA1) or phospholipase A2 (PLA2) activities using synthetic glycerophosphatidylcholines (PCs) containing α-eleostearic acid, either at the sn-1 position [1-α-eleostearoyl-2-octadecyl-rac-glycero-3-phosphocholine (EOPC)] or at the sn-2 position [1-octadecyl-2-α-eleostearoyl-rac-glycero-3-phosphocholine (OEPC)]. The substrates were coated onto the wells of microtiter plates. A nonhydrolyzable ether bond, with a non-UV-absorbing alkyl chain, was introduced at the other sn position to prevent acyl chain migration during lipolysis. Upon enzyme action, α-eleostearic acid is liberated and then solubilized into the micellar phase. The PLA1 or PLA2 activity was measured by the increase in absorbance at 272 nm due to the transition of α-eleostearic acid from the adsorbed to the soluble state. EOPC and OEPC differentiate, with excellent accuracy, between PLA1 and PLA2 activity. Lecitase(®), guinea pig pancreatic lipase-related protein 2 (known to be a PLA1 enzyme), bee venom PLA2, and porcine pancreatic PLA2 were all used to validate the assay. Compared with current assays used for continuously measuring PLA1 or PLA2 activities and/or their inhibitors, the development of this sensitive enzymatic method, using coated PC substrate analogs to natural lipids and based on the UV spectroscopic properties of α-eleostearic acid, is a significant improvement.
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Affiliation(s)
- Meddy El Alaoui
- Univ Lyon, Université Lyon 1, UMR 5246, CNRS, INSA Lyon, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Métabolismes, Enzymes et Mécanismes Moléculaires (MEM), F-69622 Villeurbanne, France Univ Lyon, INSA Lyon, UMR 5246, CNRS, Université Lyon 1, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Chimie Organique et Bioorganique (COB), F-69621 Villeurbanne, France
| | - Laurent Soulère
- Univ Lyon, INSA Lyon, UMR 5246, CNRS, Université Lyon 1, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Chimie Organique et Bioorganique (COB), F-69621 Villeurbanne, France
| | - Alexandre Noiriel
- Univ Lyon, Université Lyon 1, UMR 5246, CNRS, INSA Lyon, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Métabolismes, Enzymes et Mécanismes Moléculaires (MEM), F-69622 Villeurbanne, France
| | - Florence Popowycz
- Univ Lyon, INSA Lyon, UMR 5246, CNRS, Université Lyon 1, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Chimie Organique et Bioorganique (COB), F-69621 Villeurbanne, France
| | - Abdallah Khatib
- Univ Lyon, Université Lyon 1, UMR 5246, CNRS, INSA Lyon, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Métabolismes, Enzymes et Mécanismes Moléculaires (MEM), F-69622 Villeurbanne, France
| | - Yves Queneau
- Univ Lyon, INSA Lyon, UMR 5246, CNRS, Université Lyon 1, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Chimie Organique et Bioorganique (COB), F-69621 Villeurbanne, France
| | - Abdelkarim Abousalham
- Univ Lyon, Université Lyon 1, UMR 5246, CNRS, INSA Lyon, CPE Lyon, Institut de Chimie et de Biochimie Moléculaires et Supramoléculaires (ICBMS), Métabolismes, Enzymes et Mécanismes Moléculaires (MEM), F-69622 Villeurbanne, France
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15
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Papillon JPN, Pan M, Brousseau ME, Gilchrist MA, Lou C, Singh AK, Stawicki T, Thompson JE. Synthetic phospholipids as specific substrates for plasma endothelial lipase. Bioorg Med Chem Lett 2016; 26:3514-7. [PMID: 27344207 DOI: 10.1016/j.bmcl.2016.06.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 11/25/2022]
Abstract
We designed and prepared synthetic phospholipids that generate lyso-phosphatidylcholine products with a unique mass for convenient detection by LC-MS in complex biological matrices. We demonstrated that compound 4, formulated either as a Triton X-100 emulsion or incorporated in synthetic HDL particles can serve as a substrate for plasma EL with useful specificity.
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Affiliation(s)
- Julien P N Papillon
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, United States.
| | - Meihui Pan
- Cardiovascular and Metabolism, Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, MA 02139, United States.
| | - Margaret E Brousseau
- Cardiovascular and Metabolism, Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, MA 02139, United States
| | - Mark A Gilchrist
- Cardiovascular and Metabolism, Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, MA 02139, United States
| | - Changgang Lou
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Alok K Singh
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Todd Stawicki
- Cardiovascular and Metabolism, Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, MA 02139, United States
| | - James E Thompson
- Cardiovascular and Metabolism, Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, MA 02139, United States
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16
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Flaugnatti N, Le TTH, Canaan S, Aschtgen MS, Nguyen VS, Blangy S, Kellenberger C, Roussel A, Cambillau C, Cascales E, Journet L. A phospholipase A1
antibacterial Type VI secretion effector interacts directly with the C-terminal domain of the VgrG spike protein for delivery. Mol Microbiol 2016; 99:1099-118. [DOI: 10.1111/mmi.13292] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Nicolas Flaugnatti
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS - Aix-Marseille Université, UMR 7255, Institut de Microbiologie de la Méditerranée; 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 France
| | - Thi Thu Hang Le
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Stéphane Canaan
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, CNRS - Aix-Marseille Université, UMR 7282; 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 France
| | - Marie-Stéphanie Aschtgen
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS - Aix-Marseille Université, UMR 7255, Institut de Microbiologie de la Méditerranée; 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 France
| | - Van Son Nguyen
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Stéphanie Blangy
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Christine Kellenberger
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, CNRS - UMR 7257, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
- Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, Campus de Luminy, Case 932; 13288 Marseille Cedex 09 France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS - Aix-Marseille Université, UMR 7255, Institut de Microbiologie de la Méditerranée; 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 France
| | - Laure Journet
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS - Aix-Marseille Université, UMR 7255, Institut de Microbiologie de la Méditerranée; 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20 France
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17
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Kuge H, Akahori K, Yagyu KI, Honke K. Functional compartmentalization of the plasma membrane of neurons by a unique acyl chain composition of phospholipids. J Biol Chem 2014; 289:26783-26793. [PMID: 25096572 DOI: 10.1074/jbc.m114.571075] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In neurons, the plasma membrane is functionally separated into several distinct segments. Neurons form these domains by delivering selected components to and by confining them within each segment of the membrane. Although some mechanisms of the delivery are elucidated, that of the confinement is unclear. We show here that 1-oleoyl-2-palmitoyl-phosphatidylcholine (OPPC), a unique molecular species of phospholipids, is concentrated at the protrusion tips of several neuronal culture cells and the presynaptic area of neuronal synapses of the mouse brain. In PC12 cells, NGF-stimulated neuronal differentiation induces a phospholipase A1 activity at the protrusion tips, which co-localizes with the OPPC domain. Inhibition of the phospholipase A1 activity leads to suppression of phospholipid remodeling in the tip membrane and results in disappearance of the OPPC at the tips. In these cells, confinement of dopamine transporter and Gαo proteins to the tip was also disrupted. These findings link the lateral distribution of the molecular species of phospholipids to the formation of functional segments in the plasma membrane of neurons and to the mechanism of protein confinement at the synapse.
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Affiliation(s)
- Hideaki Kuge
- Department of Biochemistry, Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan; Center for Innovate and Translational Medicine, and Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan.
| | - Kana Akahori
- Department of Biochemistry, Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan
| | - Ken-Ichi Yagyu
- Science Research Center, Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan
| | - Koichi Honke
- Department of Biochemistry, Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan; Center for Innovate and Translational Medicine, and Kochi University Medical School, Kohasu, Okocyou, Nankoku, Kochi 783-8505, Japan.
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18
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Sun S, Dean R, Jia Q, Zenova A, Zhong J, Grayson C, Xie C, Lindgren A, Samra P, Sojo L, van Heek M, Lin L, Percival D, Fu JM, Winther MD, Zhang Z. Discovery of XEN445: a potent and selective endothelial lipase inhibitor raises plasma HDL-cholesterol concentration in mice. Bioorg Med Chem 2013; 21:7724-34. [PMID: 24211162 DOI: 10.1016/j.bmc.2013.10.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 10/08/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
Abstract
Endothelial lipase (EL) activity has been implicated in HDL metabolism and in atherosclerotic plaque development; inhibitors are proposed to be efficacious in the treatment of dyslipidemia related cardiovascular disease. We describe here the discovery of a novel class of anthranilic acids EL inhibitors. XEN445 (compound 13) was identified as a potent and selective EL inhibitor, that showed good ADME and PK properties, and demonstrated in vivo efficacy in raising plasma HDLc concentrations in mice.
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Affiliation(s)
- Shaoyi Sun
- Xenon Pharmaceuticals Inc, 200-3650 Gilmore Way, Burnaby, BC V5G 4W8, Canada.
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19
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Robert J, Lehner M, Frank S, Perisa D, von Eckardstein A, Rohrer L. Interleukin 6 stimulates endothelial binding and transport of high-density lipoprotein through induction of endothelial lipase. Arterioscler Thromb Vasc Biol 2013; 33:2699-706. [PMID: 24115033 DOI: 10.1161/atvbaha.113.301363] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE In the reverse cholesterol transport pathway, high-density lipoprotein (HDL) passes the endothelial cell barrier by mechanisms involving the scavenger receptor class B type I and the ATP-binding cassette G1. However, little is known on how inflammation influences this transendothelial transport. APPROACH AND RESULTS On stimulation with interleukin-6, cultivated primary endothelial cells showed increased binding and transport of (125)I-HDL without changing the expression of scavenger receptor class B type I and ATP-binding cassette G1. Therefore, we analyzed the involvement of endothelial lipase (EL), a known HDL-binding protein expressed by endothelial cells. Here, we show an increased EL expression after interleukin-6 stimulation. Moreover, using pharmacological inhibitors or RNA interference against EL, we demonstrated its participation in HDL binding and transport through the endothelium. Furthermore, adenovirus-mediated transfection of endothelial cells with either catalytically active or nonactive EL revealed that EL facilitates the endothelial binding and transport by both bridging and lipolysis of HDL. EL was also found responsible for the reduction of HDL particle size occurring during the specific transport through a monolayer of endothelial cells. Finally, pharmacological inhibition of EL reversed the inducing effect of interleukin-6 on HDL binding and transport. CONCLUSIONS Interleukin-6 stimulates the translocation of HDL through the endothelium, the first step in reverse cholesterol transport pathway, by enhancing EL expression. In addition, we demonstrated the role of EL in the transendothelial transport of HDL.
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Affiliation(s)
- Jérôme Robert
- From the Institute of Clinical Chemistry, University Hospital of Zurich, Zurich, Switzerland (J.R., M.L., D.P., A.v.E., L.R.); Zurich Center of Integrated Human Physiology, University of Zurich, Zurich, Switzerland (J.R., D.P., A.v.E., L.R.); and Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University Graz, Graz, Austria (S.F.)
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20
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Asano A, Nelson-Harrington JL, Travis AJ. Phospholipase B is activated in response to sterol removal and stimulates acrosome exocytosis in murine sperm. J Biol Chem 2013; 288:28104-15. [PMID: 23943622 DOI: 10.1074/jbc.m113.450981] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite a strict requirement for sterol removal for sperm to undergo acrosome exocytosis (AE), the mechanisms by which changes in membrane sterols are transduced into changes in sperm fertilization competence are poorly understood. We have previously shown in live murine sperm that the plasma membrane overlying the acrosome (APM) contains several types of microdomains known as membrane rafts. When characterizing the membrane raft-associated proteomes, we identified phospholipase B (PLB), a calcium-independent enzyme exhibiting multiple activities. Here, we show that sperm surface PLB is activated in response to sterol removal. Both biochemical activity assays and immunoblots of subcellular fractions of sperm incubated with the sterol acceptor 2-hydroxypropyl-β-cyclodextrin (2-OHCD) confirmed the release of an active PLB fragment. Specific protease inhibitors prevented PLB activation, revealing a mechanistic requirement for proteolytic cleavage. Competitive inhibitors of PLB reduced the ability of sperm both to undergo AE and to fertilize oocytes in vitro, suggesting an important role in fertilization. This was reinforced by our finding that incubation either with protein concentrate released from 2-OHCD-treated sperm or with recombinant PLB peptide corresponding to the catalytic domain was able to induce AE in the absence of other stimuli. Together, these results lead us to propose a novel mechanism by which sterol removal promotes membrane fusogenicity and AE, helping confer fertilization competence. Importantly, this mechanism provides a basis for the newly emerging model of AE in which membrane fusions occur during capacitation/transit through the cumulus, prior to any physical contact between the sperm and the oocyte's zona pellucida.
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Affiliation(s)
- Atsushi Asano
- From the Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853
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21
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Dedieu L, Serveau-Avesque C, Canaan S. Identification of residues involved in substrate specificity and cytotoxicity of two closely related cutinases from Mycobacterium tuberculosis. PLoS One 2013; 8:e66913. [PMID: 23843969 PMCID: PMC3699616 DOI: 10.1371/journal.pone.0066913] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/11/2013] [Indexed: 11/20/2022] Open
Abstract
The enzymes belonging to the cutinase family are serine enzymes active on a large panel of substrates such as cutin, triacylglycerols, and phospholipids. In the M. tuberculosis H37Rv genome, seven genes coding for cutinase-like proteins have been identified with strong immunogenic properties suggesting a potential role as vaccine candidates. Two of these enzymes which are secreted and highly homologous, possess distinct substrates specificities. Cfp21 is a lipase and Cut4 is a phospholipase A2, which has cytotoxic effects on macrophages. Structural overlay of their three-dimensional models allowed us to identify three areas involved in the substrate binding process and to shed light on this substrate specificity. By site-directed mutagenesis, residues present in these Cfp21 areas were replaced by residues occurring in Cut4 at the same location. Three mutants acquired phospholipase A1 and A2 activities and the lipase activities of two mutants were 3 and 15 fold greater than the Cfp21 wild type enzyme. In addition, contrary to mutants with enhanced lipase activity, mutants that acquired phospholipase B activities induced macrophage lysis as efficiently as Cut4 which emphasizes the relationship between apparent phospholipase A2 activity and cytotoxicity. Modification of areas involved in substrate specificity, generate recombinant enzymes with higher activity, which may be more immunogenic than the wild type enzymes and could therefore constitute promising candidates for antituberculous vaccine production.
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Affiliation(s)
- Luc Dedieu
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
| | - Carole Serveau-Avesque
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
| | - Stéphane Canaan
- CNRS - Aix-Marseille Université - Enzymologie Interfaciale et Physiologie de la Lipolyse - UMR 7282, Marseille, France
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22
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Basu D, Lei X, Josekutty J, Hussain MM, Jin W. Measurement of the phospholipase activity of endothelial lipase in mouse plasma. J Lipid Res 2012; 54:282-9. [PMID: 23103358 DOI: 10.1194/jlr.d031112] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Endothelial lipase (EL) is a major negative regulator of plasma HDL levels in mice, rabbits, and most probably, humans. Although this regulatory function is critically dependent on EL's hydrolysis of HDL phospholipids, as yet there is no phospholipase assay specific for EL in plasma. We developed such an assay for the mouse enzyme using a commercially available phospholipid-like fluorescent substrate in combination with an EL neutralizing antibody. The specificity of the assay was established using EL knockout mice and its utility demonstrated by detection of an increase in plasma EL phospholipase activity following exposure of wild-type mice to lipopolysaccharide. The assay revealed that murine pre-heparin plasma does not contain measurable EL activity, indicating that the hydrolysis of HDL phospholipids by EL in vivo likely occurs on the cell surface.
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Affiliation(s)
- Debapriya Basu
- Department of Cell Biology, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA
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23
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Connelly MA, D'Andrea MR, Qi J, Dzordzorme KC, Damiano BP. Endothelial lipase is localized to follicular epithelial cells in the thyroid gland and is moderately expressed in adipocytes. J Histochem Cytochem 2012; 60:694-705. [PMID: 22740344 DOI: 10.1369/0022155412454110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelial lipase (EL), a member of the triglyceride lipase gene family, has been shown to be a key player in HDL metabolism. Northern blots revealed that EL was highly expressed in endothelium, thyroid, lung, placenta, liver, and testis. In liver and adrenal gland, EL protein was localized with vascular endothelial cells but not parenchymal cells. EL was shown to be upregulated in tissues such as atherosclerotic plaque where it was located in macrophages, endothelial cells, and medial smooth muscle cells. The purpose of this study was to investigate the cellular localization of EL in thyroid and other tissues where EL is known to be expressed. Besides its presence in vascular endothelial and smooth muscle cells, EL protein was detected in the epithelial cells that line the follicles within the thyroid gland. EL-specific immunostaining was also found near the cell surface as well as in the cytoplasm of adipocytes. Using immunoblots, EL expression was confirmed in cultured human omental and subcutaneous adipocytes. EL expression, however, was not found in preadipocytes. These findings suggest that EL plays a role in thyroid and adipocyte biology in addition to its well-known role in endothelial function and HDL metabolism.
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Affiliation(s)
- Margery A Connelly
- Janssen Research and Development, Janssen Pharmaceutical Companies of Johnson and Johnson, Spring House, PA 19477, USA
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