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Kimura T, Kimura AK, Epand RM. Systematic crosstalk in plasmalogen and diacyl lipid biosynthesis for their differential yet concerted molecular functions in the cell. Prog Lipid Res 2023; 91:101234. [PMID: 37169310 DOI: 10.1016/j.plipres.2023.101234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/29/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023]
Abstract
Plasmalogen is a major phospholipid of mammalian cell membranes. Recently it is becoming evident that the sn-1 vinyl-ether linkage in plasmalogen, contrasting to the ester linkage in the counterpart diacyl glycerophospholipid, yields differential molecular characteristics for these lipids especially related to hydrocarbon-chain order, so as to concertedly regulate biological membrane processes. A role played by NMR in gaining information in this respect, ranging from molecular to tissue levels, draws particular attention. We note here that a broad range of enzymes in de novo synthesis pathway of plasmalogen commonly constitute that of diacyl glycerophospholipid. This fact forms the basis for systematic crosstalk that not only controls a quantitative balance between these lipids, but also senses a defect causing loss of lipid in either pathway for compensation by increase of the counterpart lipid. However, this inherent counterbalancing mechanism paradoxically amplifies imbalance in differential effects of these lipids in a diseased state on membrane processes. While sharing of enzymes has been recognized, it is now possible to overview the crosstalk with growing information for specific enzymes involved. The overview provides a fundamental clue to consider cell and tissue type-dependent schemes in regulating membrane processes by plasmalogen and diacyl glycerophospholipid in health and disease.
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Affiliation(s)
- Tomohiro Kimura
- Department of Chemistry & Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, USA.
| | - Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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2
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Dorninger F, Werner ER, Berger J, Watschinger K. Regulation of plasmalogen metabolism and traffic in mammals: The fog begins to lift. Front Cell Dev Biol 2022; 10:946393. [PMID: 36120579 PMCID: PMC9471318 DOI: 10.3389/fcell.2022.946393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/25/2022] [Indexed: 12/15/2022] Open
Abstract
Due to their unique chemical structure, plasmalogens do not only exhibit distinct biophysical and biochemical features, but require specialized pathways of biosynthesis and metabolization. Recently, major advances have been made in our understanding of these processes, for example by the attribution of the gene encoding the enzyme, which catalyzes the final desaturation step in plasmalogen biosynthesis, or by the identification of cytochrome C as plasmalogenase, which allows for the degradation of plasmalogens. Also, models have been presented that plausibly explain the maintenance of adequate cellular levels of plasmalogens. However, despite the progress, many aspects around the questions of how plasmalogen metabolism is regulated and how plasmalogens are distributed among organs and tissues in more complex organisms like mammals, remain unresolved. Here, we summarize and interpret current evidence on the regulation of the enzymes involved in plasmalogen biosynthesis and degradation as well as the turnover of plasmalogens. Finally, we focus on plasmalogen traffic across the mammalian body - a topic of major importance, when considering plasmalogen replacement therapies in human disorders, where deficiencies in these lipids have been reported. These involve not only inborn errors in plasmalogen metabolism, but also more common diseases including Alzheimer's disease and neurodevelopmental disorders.
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Affiliation(s)
- Fabian Dorninger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria,*Correspondence: Fabian Dorninger, ; Katrin Watschinger,
| | - Ernst R. Werner
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Katrin Watschinger
- Institute of Biological Chemistry, Biocenter, Medical University of Innsbruck, Innsbruck, Austria,*Correspondence: Fabian Dorninger, ; Katrin Watschinger,
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3
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Perez MA, Watts JL. Worms, Fat, and Death: Caenorhabditis elegans Lipid Metabolites Regulate Cell Death. Metabolites 2021; 11:metabo11020125. [PMID: 33672292 PMCID: PMC7926963 DOI: 10.3390/metabo11020125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/19/2021] [Accepted: 02/19/2021] [Indexed: 12/28/2022] Open
Abstract
Caenorhabditis elegans is well-known as the model organism used to elucidate the genetic pathways underlying the first described form of regulated cell death, apoptosis. Since then, C. elegans investigations have contributed to the further understanding of lipids in apoptosis, especially the roles of phosphatidylserines and phosphatidylinositols. More recently, studies in C. elegans have shown that dietary polyunsaturated fatty acids can induce the non-apoptotic, iron-dependent form of cell death, ferroptosis. In this review, we examine the roles of various lipids in specific aspects of regulated cell death, emphasizing recent work in C. elegans.
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Honsho M, Tanaka M, Zoeller RA, Fujiki Y. Distinct Functions of Acyl/Alkyl Dihydroxyacetonephosphate Reductase in Peroxisomes and Endoplasmic Reticulum. Front Cell Dev Biol 2020; 8:855. [PMID: 33042986 PMCID: PMC7517302 DOI: 10.3389/fcell.2020.00855] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/10/2020] [Indexed: 01/03/2023] Open
Abstract
Plasmalogens are a subclass of ether glycerophospholipids characterized by a vinyl-ether bond at the sn-1 position of the glycerol backbone. Plasmalogen biosynthesis is initiated in peroxisomes. At the third step of plasmalogen synthesis, alkyl-dihydroxyacetonephosphate (DHAP) is enzymatically reduced to 1-alkyl-sn-glycero-3-phospate by acyl/alkyl DHAP reductase (ADHAPR), whose activity is found in both peroxisomes and microsomes. We herein show that knockdown of ADHAPR in HeLa cells reduced the synthesis of ethanolamine plasmalogen (PlsEtn), similar to the Chinese hamster ovary cell mutant FAA.K1B deficient in ADHAPR activity. Endogenous ADHAPR and ectopically expressed FLAG-tagged ADHAPR were localized to peroxisomes and endoplasmic reticulum (ER) as a type I integral membrane protein in HeLa cells. ADHAPR targets to peroxisomes via a Pex19p-dependent class I pathway. In addition, it is also inserted into the ER via the SRP-dependent mechanism. The ADHAPR mutant lacking the N-terminal domain preferentially targets to the ER, restoring the reduced level of PlsEtn synthesis in FAA.K1B cell. In contrast, the expression of full-length ADHAPR in the mutant cells elevates the synthesis of phosphatidylethanolamine, but not PlsEtn. Taken together, these results suggest that the third step of plasmalogen synthesis is mediated by ER-localized ADHAPR.
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Affiliation(s)
- Masanori Honsho
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Megumi Tanaka
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan
| | - Raphael A Zoeller
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA, United States
| | - Yukio Fujiki
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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5
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Takahashi T, Honsho M, Abe Y, Fujiki Y. Plasmalogen mediates integration of adherens junction. J Biochem 2019; 166:423-432. [PMID: 31236591 DOI: 10.1093/jb/mvz049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 06/19/2019] [Indexed: 11/13/2022] Open
Abstract
Ether glycerolipids, plasmalogens are found in various mammalian cells and tissues. However, physiological role of plasmalogens in epithelial cells remains unknown. We herein show that synthesis of ethanolamine-containing plasmalogens, plasmenylethanolamine (PlsEtn), is deficient in MCF7 cells, an epithelial cell line, with severely reduced expression of alkyl-dihydroxyacetonephosphate synthase (ADAPS), the second enzyme in the PlsEtn biosynthesis. Moreover, expression of ADAPS or supplementation of PlsEtn containing C18-alkenyl residue delays the migration of MCF7 cells as compared to that mock-treated MCF7 and C16-alkenyl-PlsEtn-supplemented MCF7 cells. Localization of E-cadherin to cell-cell junctions is highly augmented in cells containing C18-alkenyl-PlsEtn. Together, these results suggest that PlsEtn containing C18-alkenyl residue plays a distinct role in the integrity of E-cadherin-mediated adherens junction.
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Affiliation(s)
- Takanori Takahashi
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, Japan
| | - Masanori Honsho
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
| | - Yuichi Abe
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
| | - Yukio Fujiki
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan
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6
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Abstract
Ether lipids, such as plasmalogens, are peroxisome-derived glycerophospholipids in which the hydrocarbon chain at the sn-1 position of the glycerol backbone is attached by an ether bond, as opposed to an ester bond in the more common diacyl phospholipids. This seemingly simple biochemical change has profound structural and functional implications. Notably, the tendency of ether lipids to form non-lamellar inverted hexagonal structures in model membranes suggests that they have a role in facilitating membrane fusion processes. Ether lipids are also important for the organization and stability of lipid raft microdomains, cholesterol-rich membrane regions involved in cellular signaling. In addition to their structural roles, a subset of ether lipids are thought to function as endogenous antioxidants, and emerging studies suggest that they are involved in cell differentiation and signaling pathways. Here, we review the biology of ether lipids and their potential significance in human disorders, including neurological diseases, cancer, and metabolic disorders.
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Affiliation(s)
- John M Dean
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Irfan J Lodhi
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA.
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Wanders RJA, Waterham HR, Ferdinandusse S. Peroxisomes and Their Central Role in Metabolic Interaction Networks in Humans. Subcell Biochem 2018; 89:345-365. [PMID: 30378031 DOI: 10.1007/978-981-13-2233-4_15] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Peroxisomes catalyze a number of essential metabolic functions and impairments in any of these are usually associated with major clinical signs and symptoms. In contrast to mitochondria which are autonomous organelles that can catalyze the degradation of fatty acids, certain amino acids and other compounds all by themselves, peroxisomes are non-autonomous organelles which are highly dependent on the interaction with other organelles and compartments to fulfill their role in metabolism. This includes mitochondria, the endoplasmic reticulum, lysosomes, and the cytosol. In this paper we will discuss the central role of peroxisomes in different metabolic interaction networks in humans, including fatty acid oxidation, ether phospholipid biosynthesis, bile acid synthesis, fatty acid alpha-oxidation and glyoxylate metabolism.
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Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Departments Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Departments Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Departments Clinical Chemistry and Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
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8
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Dorninger F, Forss-Petter S, Berger J. From peroxisomal disorders to common neurodegenerative diseases - the role of ether phospholipids in the nervous system. FEBS Lett 2017; 591:2761-2788. [PMID: 28796901 DOI: 10.1002/1873-3468.12788] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 07/26/2017] [Accepted: 08/07/2017] [Indexed: 01/01/2023]
Abstract
The emerging diverse roles of ether (phospho)lipids in nervous system development and function in health and disease are currently attracting growing interest. Plasmalogens, a subgroup of ether lipids, are important membrane components involved in vesicle fusion and membrane raft composition. They store polyunsaturated fatty acids and may serve as antioxidants. Ether lipid metabolites act as precursors for the formation of glycosyl-phosphatidyl-inositol anchors; others, like platelet-activating factor, are implicated in signaling functions. Consolidating the available information, we attempt to provide molecular explanations for the dramatic neurological phenotype in ether lipid-deficient human patients and mice by linking individual functional properties of ether lipids with pathological features. Furthermore, recent publications have identified altered ether lipid levels in the context of many acquired neurological disorders including Alzheimer's disease (AD) and autism. Finally, current efforts to restore ether lipids in peroxisomal disorders as well as AD are critically reviewed.
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Affiliation(s)
- Fabian Dorninger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Austria
| | - Sonja Forss-Petter
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Austria
| | - Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Austria
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9
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Abstract
Plasmalogen synthesis can be analyzed by metabolic labeling, followed by the separation of ethanolamine plasmalogens from glycerophospholipids on one-dimensional thin-layer chromatography. The vinyl-ether bond of plasmalogens is acid-labile, which allows separating plasmalogens as 2-acyl-glycerophospholipids from diacyl-glycerophospholipids.
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Affiliation(s)
- Masanori Honsho
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yukio Fujiki
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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10
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Buchert R, Tawamie H, Smith C, Uebe S, Innes AM, Al Hallak B, Ekici AB, Sticht H, Schwarze B, Lamont RE, Parboosingh JS, Bernier FP, Abou Jamra R. A peroxisomal disorder of severe intellectual disability, epilepsy, and cataracts due to fatty acyl-CoA reductase 1 deficiency. Am J Hum Genet 2014; 95:602-10. [PMID: 25439727 DOI: 10.1016/j.ajhg.2014.10.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/02/2014] [Indexed: 11/18/2022] Open
Abstract
Rhizomelic chondrodysplasia punctata (RCDP) is a group of disorders with overlapping clinical features including rhizomelia, chondrodysplasia punctata, coronal clefts, cervical dysplasia, congenital cataracts, profound postnatal growth retardation, severe intellectual disability, and seizures. Mutations in PEX7, GNPAT, and AGPS, all involved in the plasmalogen-biosynthesis pathway, have been described in individuals with RCDP. Here, we report the identification of mutations in another gene in plasmalogen biosynthesis, fatty acyl-CoA reductase 1 (FAR1), in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity. Exome analyses revealed a homozygous in-frame indel mutation (c.495_507delinsT [p.Glu165_Pro169delinsAsp]) in two siblings from a consanguineous family and compound-heterozygous mutations (c.[787C>T];[1094A>G], p.[Arg263(∗)];[Asp365Gly]) in a third unrelated individual. FAR1 reduces fatty acids to their respective fatty alcohols for the plasmalogen-biosynthesis pathway. To assess the pathogenicity of the identified mutations, we transfected human embryonic kidney 293 cells with plasmids encoding FAR1 with either wild-type or mutated constructs and extracted the lipids from the cells. We screened the lipids with gas chromatography and mass spectrometry and found that all three mutations abolished the reductase activity of FAR1, given that no fatty alcohols could be detected. We also observed reduced plasmalogens in red blood cells in one individual to a range similar to that seen in individuals with RCDP, further supporting abolished FAR1 activity. We thus expand the spectrum of clinical features associated with defects in plasmalogen biosynthesis to include FAR1 deficiency as a cause of syndromic severe intellectual disability with cataracts, epilepsy, and growth retardation but without rhizomelia.
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Affiliation(s)
- Rebecca Buchert
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Hasan Tawamie
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Christopher Smith
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Steffen Uebe
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - A Micheil Innes
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | | | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Heinrich Sticht
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Bernd Schwarze
- Department of Forensic Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Ryan E Lamont
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Jillian S Parboosingh
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Francois P Bernier
- Department of Medical Genetics, University of Calgary, Calgary, AB T2N 4N1, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Rami Abou Jamra
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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Braverman NE, Moser AB. Functions of plasmalogen lipids in health and disease. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1442-52. [PMID: 22627108 DOI: 10.1016/j.bbadis.2012.05.008] [Citation(s) in RCA: 685] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/21/2012] [Accepted: 05/09/2012] [Indexed: 12/17/2022]
Abstract
Plasmalogens are a unique class of membrane glycerophospholipids containing a fatty alcohol with a vinyl-ether bond at the sn-1 position, and enriched in polyunsaturated fatty acids at the sn-2 position of the glycerol backbone. These two features provide novel properties to these compounds. Although plasmalogens represent up to 20% of the total phospholipid mass in humans their physiological roles have been challenging to identify, and are likely to be particular to different tissues, metabolic processes and developmental stages. Their biosynthesis starts in peroxisomes, and defects at these steps cause the malformation syndrome, Rhizomelic Chondrodysplasia Punctata (RCDP). The RCDP phenotype predicts developmental roles for plasmalogens in bone, brain, lens, lung, kidney and heart. Recent studies have revealed secondary plasmalogen deficiencies associated with more common disorders and allow us to tease out additional pathways dependent on plasmalogen functions. In this review, we present current knowledge of plasmalogen biology in health and disease.
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Affiliation(s)
- Nancy E Braverman
- Department of Human Genetics and Pediatrics, McGill University-Montreal Childrens Hospital Research Institute, Montreal, Canada.
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12
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Itzkovitz B, Jiralerspong S, Nimmo G, Loscalzo M, Horovitz DDG, Snowden A, Moser A, Steinberg S, Braverman N. Functional characterization of novel mutations in GNPAT and AGPS, causing rhizomelic chondrodysplasia punctata (RCDP) types 2 and 3. Hum Mutat 2011; 33:189-97. [DOI: 10.1002/humu.21623] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 09/13/2011] [Indexed: 01/06/2023]
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Mankidy R, Ahiahonu PW, Ma H, Jayasinghe D, Ritchie SA, Khan MA, Su-Myat KK, Wood PL, Goodenowe DB. Membrane plasmalogen composition and cellular cholesterol regulation: a structure activity study. Lipids Health Dis 2010; 9:62. [PMID: 20546600 PMCID: PMC2902472 DOI: 10.1186/1476-511x-9-62] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 06/14/2010] [Indexed: 02/06/2023] Open
Abstract
Background Disrupted cholesterol regulation leading to increased circulating and membrane cholesterol levels is implicated in many age-related chronic diseases such as cardiovascular disease (CVD), Alzheimer's disease (AD), and cancer. In vitro and ex vivo cellular plasmalogen deficiency models have been shown to exhibit impaired intra- and extra-cellular processing of cholesterol. Furthermore, depleted brain plasmalogens have been implicated in AD and serum plasmalogen deficiencies have been linked to AD, CVD, and cancer. Results Using plasmalogen deficient (NRel-4) and plasmalogen sufficient (HEK293) cells we investigated the effect of species-dependent plasmalogen restoration/augmentation on membrane cholesterol processing. The results of these studies indicate that the esterification of cholesterol is dependent upon the amount of polyunsaturated fatty acid (PUFA)-containing ethanolamine plasmalogen (PlsEtn) present in the membrane. We further elucidate that the concentration-dependent increase in esterified cholesterol observed with PUFA-PlsEtn was due to a concentration-dependent increase in sterol-O-acyltransferase-1 (SOAT1) levels, an observation not reproduced by 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibition. Conclusion The present study describes a novel mechanism of cholesterol regulation that is consistent with clinical and epidemiological studies of cholesterol, aging and disease. Specifically, the present study describes how selective membrane PUFA-PlsEtn enhancement can be achieved using 1-alkyl-2-PUFA glycerols and through this action reduce levels of total and free cholesterol in cells.
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Affiliation(s)
- Rishikesh Mankidy
- Phenomenome Discoveries Inc, and Phreedom Pharma, 204-407 Downey Road, Saskatoon, SK S7N 4L8, Canada
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14
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Haller JF, Smith C, Liu D, Zheng H, Tornheim K, Han GS, Carman GM, Zoeller RA. Isolation of novel animal cell lines defective in glycerolipid biosynthesis reveals mutations in glucose-6-phosphate isomerase. J Biol Chem 2009; 285:866-77. [PMID: 19903819 DOI: 10.1074/jbc.m109.068213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Glycerolipids are structural components for membranes and serve in energy storage. We describe here the use of a photodynamic selection technique to generate a population of Chinese hamster ovary cells that display a global deficiency in glycerolipid biosynthesis. One isolate from this population, GroD1, displayed a profound reduction in the synthesis of phosphatidylcholine, phosphatidylethanolamine, and triglycerides but presented high levels of phosphatidic acid and normal levels of phosphatidylinositol synthesis. This was accompanied by a reduction in phosphatidate phosphatase 1 (PAP1) activity. Expression cloning and sequencing of the cDNA obtained from GroD1 revealed a point mutation, Gly-189 --> Glu, in glucose-6-phosphate isomerase (GPI), a glycolytic enzyme involved in an inherited disorder that results in anemia and neuromuscular symptoms in humans. GPI activity was reduced by 87% in GroD1. No significant differences were found in DNA synthesis, protein synthesis, and ATP levels, whereas glycerol 3-phosphate levels were increased in the mutant. Expression of wild-type hamster GPI restored GPI activity, glycerolipid biosynthesis, and PAP1 activity in GroD1. Two additional, independently isolated GPI-deficient mutants displayed similar phenotypes with respect to PAP1 activity and glycerolipid biosynthesis. These findings uncover a novel relationship between GPI, involved in carbohydrate metabolism, and PAP1, a lipogenic enzyme. These results may also help to explain neuromuscular symptoms associated with inherited GPI deficiency.
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Affiliation(s)
- Jorge F Haller
- Department of Physiology and Biophysics, Boston University School of Medicine, Massachusetts 02118, USA
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15
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Honsho M, Yagita Y, Kinoshita N, Fujiki Y. Isolation and characterization of mutant animal cell line defective in alkyl-dihydroxyacetonephosphate synthase: Localization and transport of plasmalogens to post-Golgi compartments. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1857-65. [DOI: 10.1016/j.bbamcr.2008.05.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 05/02/2008] [Accepted: 05/21/2008] [Indexed: 10/22/2022]
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16
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Fujiki Y, Okumoto K, Kinoshita N, Ghaedi K. Lessons from peroxisome-deficient Chinese hamster ovary (CHO) cell mutants. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1374-81. [PMID: 17045664 DOI: 10.1016/j.bbamcr.2006.09.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/05/2006] [Accepted: 09/06/2006] [Indexed: 10/24/2022]
Abstract
Cells with a genetic defect affecting a biological activity and/or a cell phenotype are generally called "cell mutants" and are a highly useful tool in genetic, biochemical, as well as cell biological research. To investigate peroxisome biogenesis and human peroxisome biogenesis disorders, more than a dozen complementation groups of Chinese hamster ovary (CHO) cell mutants defective in peroxisome assembly have been successfully isolated and established as a model system. Moreover, successful PEX gene cloning studies by taking advantage of rapid functional complementation assay of CHO cell mutants invaluably contributed to the accomplishment of isolation of pathogenic genes responsible for peroxisome biogenesis diseases. Molecular mechanisms of peroxisome assembly are currently investigated by making use of such mammalian cell mutants.
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Affiliation(s)
- Yukio Fujiki
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
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Liu D, Nagan N, Just WW, Rodemer C, Thai TP, Zoeller RA. Role of dihydroxyacetonephosphate acyltransferase in the biosynthesis of plasmalogens and nonether glycerolipids. J Lipid Res 2005; 46:727-35. [PMID: 15687349 DOI: 10.1194/jlr.m400364-jlr200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The variant CHO-K1 cell line, NRel-4, is unable to synthesize plasmalogens because of a severe reduction in dihydroxyacetonephosphate acyltransferase (DHAPAT) activity (Nagan, N., A. K. Hajra, L. K. Larkins, P. Lazarow, P. E. Purdue, W. B. Rizzo, and R. A. Zoeller. 1998. Isolation of a Chinese hamster fibroblast variant defective in dihydroxyacetonephosphate acyltransferase activity and plasmalogen biosynthesis: use of a novel two-step selection protocol. Biochem. J. 332: 273-279). Northern analysis demonstrated that the loss of this activity was attributable to a severe reduction in mRNA levels for DHAPAT. Transfection of NRel-4 cells with a plasmid bearing the human DHAPAT cDNA recovered DHAPAT activity and plasmalogen biosynthesis. Examination of clonal isolates from the transfected population showed that recovery of as little as 10% of wild-type DHAPAT activity restored plasmalogen levels to 55% of normal, whereas in one isolate, NRel-4.15, which overexpressed DHAPAT activity by 6-fold over wild-type cells, plasmalogen levels were returned only to wild-type values. Although the rate of plasmenylethanolamine biosynthesis was restored in NRel-4.15, the biosynthesis of nonether glycerolipids was either decreased or unaffected, suggesting that peroxisomal DHAPAT does not normally contribute to nonether glycerolipid biosynthesis. These data demonstrate that a defect in the gene that codes for peroxisomal DHAPAT is the primary lesion in the NRel-4 cell line and that the peroxisomal DHAPAT is essential for the biosynthesis of plasmalogens in animal cells.
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Affiliation(s)
- Dailan Liu
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
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Affiliation(s)
- N Nagan
- Department of Laboratory Medicine and Pathology, Division of Clinical Biochemistry and Immunology, Mayo Foundation Clinic, Rochester, MN 55905, USA
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Hajra AK, Larkins LK, Das AK, Hemati N, Erickson RL, MacDougald OA. Induction of the peroxisomal glycerolipid-synthesizing enzymes during differentiation of 3T3-L1 adipocytes. Role in triacylglycerol synthesis. J Biol Chem 2000; 275:9441-6. [PMID: 10734090 DOI: 10.1074/jbc.275.13.9441] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The glycerophosphate backbone for triglyceride synthesis is commonly believed to be created through the conversion of dihydroxyacetone phosphate (DHAP) by glycerophosphate dehydrogenase (GPD) to sn-glycerol 3-phosphate (GP), which is then converted by glycerophosphate acyltransferase (GPAT) to 1-acyl-GP. Consistent with this, GPD and GPAT are highly induced during differentiation of mouse 3T3-L1 preadipocytes. While the acyl dihydroxyacetone phosphate (acyl-DHAP) pathway for glycerolipid synthesis is commonly believed to be involved only in glycerol ether lipid synthesis, we report here that during conversion of 3T3-L1 preadipocytes to adipocytes, the specific activity of peroxisomal DHAP acyltransferase (DHAPAT) is increased by 9-fold in 6 days, while acyl-DHAP:NADPH reductase is induced by 5-fold. A parallel increase in the catalase (the peroxisomal marker enzyme) activity is also seen. In contrast, the specific activity of alkyl-DHAP synthase, the enzyme catalyzing the synthesis of the ether bond, is decreased by 60% during the same period. Unlike microsomal GPAT, the induced DHAPAT is found to have high activity at pH 5.5 and is resistant to inhibition by sulfhydryl agents, heat, and proteolysis. On subcellular fractionation, DHAPAT is found to be associated with microperoxisomes whereas GPAT activity is mainly present in microsomes. Northern blot analyses reveal that induction of DHAPAT can be largely explained through increases in DHAPAT mRNA. A comparison of microsomal and peroxisomal glycerolipid synthetic pathways, using D-[3-(3)H, U-(14)C]glucose as the precursor of the lipid glycerol backbone shows that about 40-50% of triglyceride is synthesized via the acyl-DHAP pathway. These results indicate that the acyl-DHAP pathway is important not only for the synthesis of ether lipids, but also for the synthesis of triacylglycerol and other non-ether glycerolipids.
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Affiliation(s)
- A K Hajra
- Department of Biological Chemistry and Mental Health Research Institute, The University of Michigan, Ann Arbor, Michigan 48104-1687, USA.
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Lee TC. Biosynthesis and possible biological functions of plasmalogens. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1394:129-45. [PMID: 9795186 DOI: 10.1016/s0005-2760(98)00107-6] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- T C Lee
- Basic and Applied Research, Oak Ridge Institute for Science and Education/Oak Ridge Associated Universities, Oak Ridge, TN 37831-0117, USA
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Batenburg JJ, Haagsman HP. The lipids of pulmonary surfactant: dynamics and interactions with proteins. Prog Lipid Res 1998; 37:235-76. [PMID: 10193527 DOI: 10.1016/s0163-7827(98)00011-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- J J Batenburg
- Laboratory of Veterinary Biochemistry, Graduate School of Animal Health, Utrecht University, The Netherlands.
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Nagan N, Hajra AK, Larkins LK, Lazarow P, Purdue PE, Rizzo WB, Zoeller RA. Isolation of a Chinese hamster fibroblast variant defective in dihydroxyacetonephosphate acyltransferase activity and plasmalogen biosynthesis: use of a novel two-step selection protocol. Biochem J 1998; 332 ( Pt 1):273-9. [PMID: 9576878 PMCID: PMC1219478 DOI: 10.1042/bj3320273] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have developed a two-step selection protocol to generate a population of Chinese hamster ovary (CHO) cell variants that are plasmalogen-deficient, but contain intact, functional peroxisomes (plasmalogen-/peroxisome+). This involved sequential exposures of a mutagenized cell population to photodynamic damage by using two different pyrene-labelled sensors, 9-(1'-pyrene)nonanol and 12-(1'-pyrene)dodecanoic acid. By this procedure we generated several isolates, all except one of which displayed a severe decrease in plasmalogen biosynthesis. Further characterization of one of the plasmalogen-deficient isolates, NRel-4, showed that it contained intact, functional peroxisomes. Whole-cell homogenates from NRel-4 displayed severely decreased dihydroxyacetone phosphate acyltransferase, which catalyses the first step in plasmalogen biosynthesis. NRel-4 and another, recently described, plasmalogen-deficient cell line, NZel-1 [Nagan, Hajra, Das, Moser, Moser, Lazarow, Purdue and Zoeller (1997) Proc. Natl. Acad. Sci. U.S. A. 94, 4475-4480] were hypersensitive to singlet oxygen, supporting the notion of plasmalogens as radical oxygen scavengers. Wild-type-like resistance could be conferred on NRel-4 upon restoration of plasmalogen content by supplementation with a bypass compound, sn-1-hexadecylglycerol. NRel-4 and other plasmalogen-/peroxisome+ strains will allow us to examine further the role of ether lipids in cellular functions without complications associated with peroxisome deficiency, and might serve as an animal cell model for certain forms of the human genetic disorder rhizomelic chondrodysplasia punctata.
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Affiliation(s)
- N Nagan
- Department of Biophysics, Boston University School of Medicine, 80 East Concord Street, Boston, MA 02118, USA
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James PF, Zoeller RA. Isolation of animal cell mutants defective in long-chain fatty aldehyde dehydrogenase. Sensitivity to fatty aldehydes and Schiff's base modification of phospholipids: implications for Sj-ogren-Larsson syndrome. J Biol Chem 1997; 272:23532-9. [PMID: 9295289 DOI: 10.1074/jbc.272.38.23532] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Using tritium suicide, we have isolated a variant of the Chinese hamster ovary cell line, CHO-K1, that is deficient in long-chain fatty alcohol:NAD+ oxidoreductase (FAO; EC 1.1.1.192). Specifically, it was the fatty aldehyde dehydrogenase component that was affected. The enzymatic deficiency found in this mutant strain, designated FAA. K1A, was similar to that displayed by fibroblasts from patients with Sjögren-Larsson syndrome (SLS), an inheritable neurocutaneous disorder. Complementation analyses suggested that the deficiency in fatty alcohol oxidation in the FAA.K1A cells and the SLS fibroblasts is a result of lesions in homologous genes. The FAA.K1A cells were unable to convert long chain fatty aldehydes to the corresponding fatty acids. This resulted in a hypersensitivity of the FAA.K1A cells to the cytotoxic effects of long chain fatty aldehydes. The difference between the mutant and wild-type cells was most obvious when using fatty aldehydes between 14 and 20 carbons, with the greatest difference between wild-type and mutant cells found when using octadecanal. Fibroblasts from a patient with SLS also displayed the hypersensitivity phenotype when compared with FAldDH+ human fibroblasts. In both CHO and human FAldDH- cell lines, addition of long chain fatty aldehydes to the medium caused a dramatic increase in aldehyde-modified phosphatidylethanolamine, presumably through Schiff's base addition to the primary amine of the ethanolamine head group. When 25 microM hexadecanal was added to the growth medium, approximately 10% of the phosphatidylethanolamine was found in the fatty aldehyde-modified form in FAA.K1A, although this was not observed in wild-type cells. Modified phosphatidylethanolamine could be detected in FAldDH- cells even when exogenous fatty aldehydes were not added to the medium. We propose a possible role for fatty aldehydes, or other aldehydic species, in mediating some of the symptoms associated with Sjögren-Larsson syndrome.
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Affiliation(s)
- P F James
- Department of Biophysics, Center for Advanced Biomedical Research, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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