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Goh YQ, Cheam G, Wang Y. Understanding Choline Bioavailability and Utilization: First Step Toward Personalizing Choline Nutrition. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:10774-10789. [PMID: 34392687 DOI: 10.1021/acs.jafc.1c03077] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Choline is an essential macronutrient involved in neurotransmitter synthesis, cell-membrane signaling, lipid transport, and methyl-group metabolism. Nevertheless, the vast majority are not meeting the recommended intake requirement. Choline deficiency is linked to nonalcoholic fatty liver disease, skeletal muscle atrophy, and neurodegenerative diseases. The conversion of dietary choline to trimethylamine by gut microbiota is known for its association with atherosclerosis and may contribute to choline deficiency. Choline-utilizing bacteria constitutes less than 1% of the gut community and is modulated by lifestyle interventions such as dietary patterns, antibiotics, and probiotics. In addition, choline utilization is also affected by genetic factors, further complicating the impact of choline on health. This review overviews the complex interplay between dietary intakes of choline, gut microbiota and genetic factors, and the subsequent impact on health. Understanding of gut microbiota metabolism of choline substrates and interindividual variability is warranted in the development of personalized choline nutrition.
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Affiliation(s)
- Ying Qi Goh
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921
| | - Guoxiang Cheam
- School of Biological Sciences, Nanyang Technological University, Singapore 639798
| | - Yulan Wang
- Singapore Phenome Center, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921
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Nilsson Å, Duan RD. Pancreatic and mucosal enzymes in choline phospholipid digestion. Am J Physiol Gastrointest Liver Physiol 2019; 316:G425-G445. [PMID: 30576217 DOI: 10.1152/ajpgi.00320.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The digestion of choline phospholipids is important for choline homeostasis, lipid signaling, postprandial lipid and energy metabolism, and interaction with intestinal bacteria. The digestion is mediated by the combined action of pancreatic and mucosal enzymes. In the proximal small intestine, hydrolysis of phosphatidylcholine (PC) to 1-lyso-PC and free fatty acid (FFA) by the pancreatic phospholipase A2 IB coincides with the digestion of the dietary triacylglycerols by lipases, but part of the PC digestion is extended and must be mediated by other enzymes as the jejunoileal brush-border phospholipase B/lipase and mucosal secreted phospholipase A2 X. Absorbed 1-lyso-PC is partitioned in the mucosal cells between degradation and reacylation into chyle PC. Reutilization of choline for hepatic bile PC synthesis, and the reacylation of 1-lyso-PC into chylomicron PC by the lyso-PC-acyl-CoA-acyltransferase 3 are important features of choline recycling and postprandial lipid metabolism. The role of mucosal enzymes is emphasized by sphingomyelin (SM) being sequentially hydrolyzed by brush-border alkaline sphingomyelinase (alk-SMase) and neutral ceramidase to sphingosine and FFA, which are well absorbed. Ceramide and sphingosine-1-phosphate are generated and are both metabolic intermediates and important lipid messengers. Alk-SMase has anti-inflammatory effects that counteract gut inflammation and tumorigenesis. These may be mediated by multiple mechanisms including generation of sphingolipid metabolites and suppression of autotaxin induction and lyso-phosphatidic acid formation. Here we summarize current knowledge on the roles of pancreatic and mucosal enzymes in PC and SM digestion, and its implications in intestinal and liver diseases, bacterial choline metabolism in the gut, and cholesterol absorption.
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Affiliation(s)
- Åke Nilsson
- Department of Clow-linical Sciences Lund, Division of Medicine, Gastroenterology, Lund University , Lund , Sweden
| | - Rui-Dong Duan
- Gastroenterology and Nutrition Laboratory, Department of Clinical Sciences, Lund University , Lund , Sweden
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3
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Sengupta B, Narasimhulu CA, Parthasarathy S. Novel technique for generating macrophage foam cells for in vitro reverse cholesterol transport studies. J Lipid Res 2013; 54:3358-72. [PMID: 24115226 PMCID: PMC3826683 DOI: 10.1194/jlr.m041327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Generation of foam cells, an essential step for reverse cholesterol transport studies, uses the technique of receptor-dependent macrophage loading with radiolabeled acetylated LDL. In this study, we used the ability of a biologically relevant detergent molecule, lysophosphatidylcholine (lyso-PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabeled cholesterol/lyso-PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month of storage. Macrophages incubated with cholesterol or CE (unlabeled, fluorescently labeled, or radiolabeled)/lyso-PtdCho mixed micelles accumulated CE as documented by microscopy, lipid staining, labeled oleate incorporation, and by TLC. Such foam cells unloaded cholesterol when incubated with HDL but not with oxidized HDL. We propose that stable cholesterol or CE/lyso-PtdCho micelles would offer advantages over existing methods.
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Affiliation(s)
- Bhaswati Sengupta
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827
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Riekhof WR, Voelker DR. Uptake and utilization of lyso-phosphatidylethanolamine by Saccharomyces cerevisiae. J Biol Chem 2006; 281:36588-96. [PMID: 17015438 DOI: 10.1074/jbc.m608851200] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylethanolamine (PtdEtn) is synthesized by multiple pathways located in different subcellular compartments in yeast. Strains defective in the synthesis of PtdEtn via phosphatidylserine (PtdSer) synthase/decarboxylase are auxotrophic for ethanolamine, which must be transported into the cell and converted to phospholipid by the cytidinediphosphate-ethanolamine-dependent Kennedy pathway. We now demonstrate that yeast strains with psd1Delta psd2Delta mutations, devoid of PtdSer decarboxylases, import and acylate exogenous 1-acyl-2-hydroxyl-sn-glycero-3-phosphoethanolamine (lyso-PtdEtn). Lyso-PtdEtn supports growth and replaces the mitochondrial pool of PtdEtn much more efficiently than and independently of PtdEtn derived from the Kennedy pathway. Deletion of both the PtdSer decarboxylase and Kennedy pathways yields a strain that is a stringent lyso-PtdEtn auxotroph. Evidence for the specific uptake of lyso-PtdEtn by yeast comes from analysis of strains harboring deletions of the aminophospholipid translocating P-type ATPases (APLTs). Elimination of the APLTs, Dnf1p and Dnf2p, or their noncatalytic beta-subunit, Lem3p, blocked the import of radiolabeled lyso-PtdEtn and resulted in growth inhibition of lyso-PtdEtn auxotrophs. In cell extracts, lyso-PtdEtn is rapidly converted to PtdEtn by an acyl-CoA-dependent acyltransferase. These results now provide 1) an assay for APLT function based on an auxotrophic phenotype, 2) direct demonstration of APLT action on a physiologically relevant substrate, and 3) a genetic screen aimed at finding additional components that mediate the internalization, trafficking, and acylation of exogenous lyso-phospholipids.
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Affiliation(s)
- Wayne R Riekhof
- Department of Medicine, Program in Cell Biology, National Jewish Medical and Research Center, Denver, Colorado 80206, USA
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Yamashita A, Kamata R, Kawagishi N, Nakanishi H, Suzuki H, Sugiura T, Waku K. Roles of C-terminal processing, and involvement in transacylation reaction of human group IVC phospholipase A2 (cPLA2gamma). J Biochem 2005; 137:557-67. [PMID: 15944408 DOI: 10.1093/jb/mvi067] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The phospholipase A2s (PLA2s) are a diverse group of enzymes that hydrolyze the sn-2 fatty acid from phospholipids and play a role in a wide range of physiological functions. A 61-kDa calcium-independent PLA2, termed cPLA2gamma, was identified as an ortholog of cPLA2alpha with approximately 30% overall sequence identity. cPLA2gamma contains a potential prenylation motif at its C terminus, and is known to have PLA2 and lysophospholipase activities, but its physiological roles have not been clarified. In the present study, we expressed various forms of recombinant cPLA2gamma, including non-prenylated and non-cleaved forms, in order to investigate the effects of C-terminal processing. We examined the expression of the wild type and non-prenylated (SCLA) forms of cPLA2gamma, and found that the SCLA form was expressed normally and retained almost full activity. Expression of the prenylated and non-cleaved form of cPLA2gamma using yeast mutants lacking prenyl protein proteases AFC1 (a-factor-converting enzyme) and RCE1 (Ras-converting enzyme) revealed decreased expression in the mutant strain compared to that in the wild type yeast, suggesting that complete C-terminal processing is important for the functional expression of cPLA2gamma. In addition, cPLA2gamma was found to have coenzyme A (CoA)-independent transacylation and lysophospholipid (LPL) dismutase (LPLase/transacylase) activities, suggesting that it may be involved in fatty acid remodeling of phospholipids and the clearance of toxic lysophospholipids in cells.
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Affiliation(s)
- Atsushi Yamashita
- Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa 199-0195.
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Shen H, Howles P, Tso P. From interaction of lipidic vehicles with intestinal epithelial cell membranes to the formation and secretion of chylomicrons. Adv Drug Deliv Rev 2001; 50 Suppl 1:S103-25. [PMID: 11576698 DOI: 10.1016/s0169-409x(01)00181-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipophilic drugs are carried by chylomicrons that are secreted by the small intestine and transported in lymph. This review discusses the digestion, uptake, and transport of dietary lipids and the impact that these processes have on the absorption of lipophilic drugs by the gastrointestinal tract. This chapter complements Dr. Chris Potter's chapter on the "pre-absorptive" events of drug processing and solubilization. This chapter reviews the digestion of lipids in the gastric and intestinal lumen and the role of bile salts in the solubilization of lipid digestion products for uptake by the gut. Both the passive and active uptake of lipid digestion products is discussed. How intestinal lipid transporters located at the brush border membrane may play a role in the uptake of lipids by the enterocytes is examined, as is the regulation of the absorption of cholesterol by the human ATP-binding cassette transporter-1 (ABC1). The intracellular trafficking and the resynthesis of complex lipids from lipid digestion products are explored, and the formation and secretion of chylomicrons are described.
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Affiliation(s)
- H Shen
- Department of Pathology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
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Affiliation(s)
- A Wang
- Department of Chemistry and Biochemistry, Revelle College and School of Medicine, University of California at San Diego, La Jolla, CA 92093-0601, USA
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8
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Sugimoto H, Yamashita S. Characterization of the transacylase activity of rat liver 60-kDa lysophospholipase-transacylase. Acyl transfer from the sn-2 to the sn-1 position. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1438:264-72. [PMID: 10320809 DOI: 10.1016/s1388-1981(99)00059-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Rat liver 60-kDa lysophospholipase-transacylase catalyzes not only the hydrolysis of 1-acyl-sn-glycero-3-phosphocholine, but also the transfer of its acyl chain to a second molecule of 1-acyl-sn-glycero-3-phosphocholine to form phosphatidylcholine (H. Sugimoto, S. Yamashita, J. Biol. Chem. 269 (1994) 6252-6258). Here we report the detailed characterization of the transacylase activity of the enzyme. The enzyme mediated three types of acyl transfer between donor and acceptor lipids, transferring acyl residues from: (1) the sn-1 to -1(3); (2) sn-1 to -2; and (3) sn-2 to -1 positions. In the sn-1 to -1(3) transfer, the sn-1 acyl residue of 1-acyl-sn-glycero-3-phosphocholine was transferred to the sn-1(3) positions of glycerol and 2-acyl-sn-glycerol, producing 1(3)-acyl-sn-glycerol and 1,2-diacyl-sn-glycerol, respectively. In the sn-1 to -2 transfer, the sn-1 acyl residue of 1-acyl-sn-glycero-3-phosphocholine was transferred to not only the sn-2 positions of 1-acyl-sn-glycero-3-phosphocholine, but also 1-acyl-sn-glycero-3-phosphoethanolamine, producing phosphatidylcholine and phosphatidylethanolamine, respectively. 1-Acyl-sn-glycero-3-phospho-myo-inositol and 1-acyl-sn-glycero-3-phosphoserine were much less effectively transacylated by the enzyme. In the sn-2 to -1 transfer, the sn-2 acyl residue of 2-acyl-sn-glycero-3-phosphocholine was transferred to the sn-1 position of 2-acyl-sn-glycero-3-phosphocholine and 2-acyl-sn-glycero-3-phosphoethanolamine, producing phosphatidylcholine and phosphatidylethanolamine, respectively. Consistently, the enzyme hydrolyzed the sn-2 acyl residue from 2-acyl-sn-glycero-3-phosphocholine. By the sn-2 to -1 transfer activity, arachidonic acid was transferred from the sn-2 position of donor lipids to the sn-1 position of acceptor lipids, thus producing 1-arachidonoyl phosphatidylcholine. When 2-arachidonoyl-sn-glycero-3-phosphocholine was used as the sole substrate, diarachidonoyl phosphatidylcholine was synthesized at a rate of 0.23 micromol/min/mg protein. Thus, 60-kDa lysophospholipase-transacylase may play a role in the synthesis of 1-arachidonoyl phosphatidylcholine needed for important cell functions, such as anandamide synthesis.
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Affiliation(s)
- H Sugimoto
- Department of Biochemistry, Gunma University School of Medicine, Maebashi 371-8511, Japan
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Toyoda T, Sugimoto H, Yamashita S. Sequence, expression in Escherichia coli, and characterization of lysophospholipase II. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1437:182-93. [PMID: 10064901 DOI: 10.1016/s1388-1981(99)00007-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Here we report the sequence, expression in Escherichia coli cells, and characterization of a new small-form lysophospholipase named lysophospholipase II from mouse embryo. The cDNA clone was found and identified among mouse expressed sequence tags in the database search for the homologue of lysophospholipase I previously cloned from rat liver (H. Sugimoto et al., J. Biol. Chem. 271 (1996) 7705-7711). The predicted amino acids sequence contained 231 residues with a calculated molecular weight of 24794, and showed 64% identity to that of lysophospholipase I with the Gly-X-Ser-X-Gly esterase/lipase consensus. The lacZ fusion protein expressed in E. coli cells exhibited lysophospholipase activity and reacted with antibody raised against previously purified pig gastric lysophospholipase II (H. Sunaga et al., Biochem. J. 308 (1995) 551-557), but not with antibody against rat liver lysophospholipase I. The expressed enzyme was purified to a specific activity of 0.15 micromol/min per mg by DEAE-Sepharose A-500 chromatography. The enzyme preferentially utilized zwitterionic lysophospholipids in the order of lysophosphatidylcholine>lysophosphatidylethanolamine, but poorly acidic lysophospholipids, such as lysophosphatidylserine, lysophosphatidylinositol, and lysophosphatidic acid. Not only the 1-acyl isomer, but also the 2-acyl isomer were deacylated. Northern blot analysis and reverse transcription-polymerase chain reaction revealed that lysophospholipase II transcript as well as lysophospholipase I transcript was widely distributed in mouse tissues.
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Affiliation(s)
- T Toyoda
- Department of Biochemistry, Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi, Gunma 371-8511, Japan
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Ksenzenko SM, Davidson SB, Saba AA, Franko AP, Raafat AM, Diebel LN, Dulchavsky SA. Effect of triiodothyronine augmentation on rat lung surfactant phospholipids during sepsis. J Appl Physiol (1985) 1997; 82:2020-7. [PMID: 9173972 DOI: 10.1152/jappl.1997.82.6.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Surfactant functional effectiveness is dependent on phospholipid compositional integrity; sepsis decreases this through an undefined mechanism. Sepsis-induced hypothyroidism is commensurate and may be related. This study examines the effect of 3,3',5-triiodo-L-thyronine (T3) supplementation on surfactant composition and function during sepsis. Male Sprague-Dawley rats underwent sham laparotomy (Sham) or cecal ligation and puncture (CLP) with or without T3 supplementation [CLP/T3 (3 ng/h)]. After 6, 12, or 24 h, surfactant was obtained by lavage. Function was assessed by a pulsating bubble surfactometer and in vivo compliance studies. Sepsis produced a decrease in surfactant phosphatidylglycerol and phosphatidic acid, with an increase in lesser surface-active lipids phosphatidylserine and phosphatidylinositol. Phosphatidylcholine content was not significantly changed. Sepsis caused an alteration in the fatty acid composition and an increase in saturation in most phospholipids. Hormonal replacement attenuated these changes. Lung compliance and surfactant adsorption were reduced by sepsis and maintained by T3 treatment. Thyroid hormone may have an active role in lung functional preservation through maintenance of surfactant homeostasis during sepsis.
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Affiliation(s)
- S M Ksenzenko
- Department of Surgery, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Patton GM, Fasulo JM, Robins SJ. Hepatic phosphatidylcholines: evidence for synthesis in the rat by extensive reutilization of endogenous acylglycerides. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)39964-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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12
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Sugimoto H, Yamashita S. Purification, characterization, and inhibition by phosphatidic acid of lysophospholipase transacylase from rat liver. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37595-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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13
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Premkumar N, Sun GY, MacQuarrie RA. Acylation of lysophosphatidylcholine by brain membranes. J Neurosci Res 1993; 35:321-6. [PMID: 8350392 DOI: 10.1002/jnr.490350312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Brain microsomes catalyze the acylation of lysophosphatidylcholine (lysoPtdCho) in the presence and absence of added CoA derivatives. The catalytic activity is distributed widely in various subcellular fractions from rat or bovine cerebral cortex as measured by the conversion of 1-[14C]palmitoyl-sn-glycero-3-phosphocholine to [14C]PtdCho. Analysis of this latter compound revealed that the dipalmitoyl derivative is the predominant molecular species, which is formed in this reaction by transacylation between two [14C]lysoPtdCho molecules. This lysoPtdCho: lysoPtdCho transacylation reaction was enhanced several-fold by the addition of oleoyl-CoA, which also is an effective donor of acyl groups in the acyl-CoA: lysoPtdCho acyltransferase-catalyzed reaction. Measurements of the initial velocity of the transacylation reaction were used to determine kinetic constants. Apparent Km values for lysoPtdCho in the presence and absence of oleoyl-CoA were 29 microM and 104 microM, respectively, and the corresponding maximal velocities were 0.11 and 1.06 nmol.min-1.mg-1, respectively. Oleoyl-CoA at 4 microM produced half-maximal stimulation of the transacylation reaction. CoA also stimulated the rate of conversion of [14C]lysoPtdCho to [14C]PtdCho, either in the presence or absence of oleoyl-CoA, with a half-maximal effect of CoA at 80 microM. These results may be important in understanding the regulation of PtdCho synthesis and the mechanism by which acyl group composition of this compound is controlled.
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Affiliation(s)
- N Premkumar
- ABC Laboratories, School of Medicine, University of Missouri, Columbia
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14
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Venable M, Olson S, Nieto M, Wykle R. Enzymatic studies of lyso platelet-activating factor acylation in human neutrophils and changes upon stimulation. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53052-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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15
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Snyder F, Lee TC, Blank ML. The role of transacylases in the metabolism of arachidonate and platelet activating factor. Prog Lipid Res 1992; 31:65-86. [PMID: 1641397 DOI: 10.1016/0163-7827(92)90016-c] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- F Snyder
- Oak Ridge Associated Universities, Medical Sciences Division, TN 37831-0117
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16
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Weiss BA, Insel PA. Intracellular Ca2+ and protein kinase C interact to regulate alpha 1-adrenergic- and bradykinin receptor-stimulated phospholipase A2 activation in Madin-Darby canine kidney cells. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52219-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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17
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Morash SC, Cook HW, Spence MW. Lysophosphatidylcholine as an intermediate in phosphatidylcholine metabolism and glycerophosphocholine synthesis in cultured cells: an evaluation of the roles of 1-acyl- and 2-acyl-lysophosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 1004:221-9. [PMID: 2752020 DOI: 10.1016/0005-2760(89)90271-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Previous studies in our laboratory have shown that the principal pathway of phosphatidylcholine (PtdCho) degradation in cultured mouse N1E-115 neuroblastoma, C6 rat glioma, primary rat brain glia and human fibroblasts is PtdCho----lysophosphatidylcholine (lysoPtdCho)----glycerophosphocholine (GroPCho)----glycerophosphate plus choline (Morash, S.C. et al. (1988) Biochim. Biophys. Acta 961, 194-202). GroPCho is the first quantitatively major degradation product in this pathway, and could be formed by phospholipases A1 or A2, followed by lysophospholipase, or by a co-ordinated attack releasing both fatty acids by phospholipase B. The quality and quantities of lysoPtdCho present in cells reflect the nature of the initial hydrolysis step (A1 or A2), specificities of the lysophospholipases, and activities of acyltransferases that form PtdCho from lysoPtdCho. The present study was undertaken to elucidate the relative importance of these pathways by examining the fate of exogenous 1-acyl and 2-acyl-lysoPtdCho incubated with N1E-115 and C6 cells in culture. By fatty acid composition, endogenous lysoPtdCho was found to be mainly 1-acyl in both cell types based on a predominance of saturated acyl species; this suggested either preferential further deacylation or reacylation of 2-acyl-lysoPtdCho, or that 2-acyl-lysoPtdCho was not formed. Exogenous 1- and 2-acyl-lysoPtdCho specifically radiolabelled with choline and/or fatty acid were incubated either singly or as equimolar mixtures with cells. Cell association was rapid and not reversible by washing and both species were taken up at similar rates. The 2-acyl species was acylated to PtdCho faster than the 1-acyl species in both cell lines. Acylation of both lyso species was higher in C6 compared to N1E-115 cells. Hydrolysis of lysoPtdCho to GroPCho was higher in N1E-115 cells and with 1-acyl-lysoPtdCho. Transacylation between two molecules of lysoPtdCho was a minor pathway. These results document the variety and relative importance of reactions of lysoPtdCho metabolism; under similar conditions, 1- and 2-acyl-lysoPtdCho are handled differently. Both species turn over actively, but only the 1-acyl species accumulates while 2-acyl-lysoPtdCho is likely to be reacylated to form PtdCho.
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Affiliation(s)
- S C Morash
- Department of Biochemistry, Dalhousie University, Halifax, Canada
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18
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Nakagawa Y, Waku K. The metabolism of glycerophospholipid and its regulation in monocytes and macrophages. Prog Lipid Res 1989; 28:205-43. [PMID: 2694177 DOI: 10.1016/0163-7827(89)90013-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Y Nakagawa
- Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan
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19
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Serrano R. Structure and function of proton translocating ATPase in plasma membranes of plants and fungi. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 947:1-28. [PMID: 2894226 DOI: 10.1016/0304-4157(88)90017-2] [Citation(s) in RCA: 336] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- R Serrano
- European Molecular Biology Laboratory, Heidelberg (F.R.G.)
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20
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Eskelson CD, Stiffel V, Owen JA, Chvapil M, Vickers A, Brendel K. Changes in the fatty acid profile of lung, liver and serum of rats intratracheally given silica. Life Sci 1988; 42:1455-67. [PMID: 2832679 DOI: 10.1016/0024-3205(88)90056-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The esterified (E) and nonesterified (NE) fatty acid level and profile in the lung, serum, and liver of rats are significantly altered after intratracheal administration of silica. The changes include a silica-specific increase of the total long chain (C16-C20:4) fatty acid content in the lung, and a decrease in the serum and liver of both groups of rats intratracheally given silica and/or saline. In the silicotic lung, arachidonate and palmitate accumulated at the highest rate. A heat-labile, high-molecular weight component from lung homogenates increases lipogenesis in isolated hepatocytes in vitro. These findings, taken together with evidence indicating increased lipogenesis in the liver of rats treated with silica under identical conditions, suggest a lung-liver communication mechanism which coordinates lipid uptake by the lung and lipid synthesis and release by the liver. The stimulatory factor identified in lung homogenates might play an important regulatory role-for hepatic lipogenesis in rats developing silicotic lungs.
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Affiliation(s)
- C D Eskelson
- Department of Surgery, University of Arizona Health Sciences Center, Tucson 85724
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Metz SA. Metabolism of lysophospholipids in intact rat islets. The insulin secretagogue p-hydroxymercuribenzoic acid impairs lysophosphatidylcholine catabolism and permits its accumulation. Biochem J 1987; 241:863-9. [PMID: 3297039 PMCID: PMC1147640 DOI: 10.1042/bj2410863] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Although recent studies implicate lysophospholipids (lyso-PLs) in stimulus-secretion coupling in the pancreatic islet, almost no data on lyso-PL metabolism therein exist. Therefore, intact rat islets were loaded with insulinotropic and non-toxic concentrations of 1-[14C]palmitoyl-lysophosphatidylcholine (lyso-PC) via transbilayer movement, and its metabolic fate was studied. The time-dependent hydrolysis of lyso-PC to fatty acid (lysophospholipase activity), its conversion to phosphatidylcholine (putative acyltransferase activity) and, to a lesser degree, the appearance of label in phosphatidylethanolamine (putative transacylase or base exchange activity) were observed. p-Hydroxymercuribenzoic acid (PHMB) at 100 microM (a concentration previously demonstrated to elicit potent exocytotic insulin release) inhibited all three activities (by 56, 46 and 75%, respectively) and led to the intracellular accumulation of lyso-PC. Antimycin A inhibited phosphatidylcholine formation but not lysophospholipase activity; lyso-PC did not accumulate, implying that blockade of both of the major metabolic pathways is required to induce a detectable increment in lyso-PC levels. Calculations derived from data using the lowest effective insulinotropic concentration of lyso-PC suggested that increments in lyso-PC accumulation at critical membrane sites of less than 10-15% above basal values are sufficient to trigger insulin release. Since PHMB elicited increments of 50-100% in lyso-PC after its translocation into islets, support is provided for the earlier contention that lyso-PLs mediate the insulinotropic effect of PHMB. In addition, these studies may provide a more precise experimental paradigm for future studies of islet lyso-PL metabolism.
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Burrier RE, Brecher P. Binding of lysophosphatidylcholine to the rat liver fatty acid binding protein. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 879:229-39. [PMID: 3768402 DOI: 10.1016/0005-2760(86)90107-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In this study, lysophosphatidylcholine (lysoPC) was shown to bind to a fatty acid binding protein isolated from rat liver. To demonstrate the binding, lysoPC was incorporated into multilamellar liposomes and incubated with protein. For comparison, binding of both lysoPC and fatty acid to liver fatty acid binding protein, albumin, and heart fatty acid binding protein were measured. At conditions where palmitic acid bound to liver fatty acid binding protein and albumin at ligand to protein molar ratios of 2:1 and 5:1, respectively, lysoPC binding occurred at molar ratios of 0.4:1 and 1:1. LysoPC did not bind to heart fatty acid binding protein under conditions where fatty acid bound at a molar ratio of 2:1. Competition experiments between lysoPC and fatty acid to liver fatty acid binding protein indicated separate binding sites for each ligand. An equilibrium dialysis cell was used to demonstrate that liver fatty acid binding protein was capable of transporting lysoPC from liposomes to rat liver microsomes, thereby facilitating its metabolism. These studies suggest that liver fatty acid binding protein may be involved in the intracellular metabolism of lysoPC as well as fatty acids, and that functional differences may exist between rat liver and heart fatty acid binding protein.
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Cornic M, Breton M, Colard O. Acylation of 1-alkyl- and 1-acyl-lysophospholipids by rat platelets. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1986; 18 Suppl:43-9. [PMID: 3095852 DOI: 10.1016/0031-6989(86)90037-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Robinson M, Blank ML, Snyder F. Acylation of lysophospholipids by rabbit alveolar macrophages. Specificities of CoA-dependent and CoA-independent reactions. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)39536-4] [Citation(s) in RCA: 139] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
In order to examine the effects of paraquat on pulmonary lipid metabolism rabbits were exposed to double distilled water by aerosol, or 250 mg paraquat in double distilled water. One hour prior to sacrifice, a group of rabbits were injected with [2-14C]-acetate. The levels of phospholipids, fatty acids, cholesterol, and triglycerides were determined as were their 14C-contents in the lung, bronchoalveolar lavage fluid, serum, and liver. The serum of paraquat-exposed animals contained significantly increased levels of phospholipids, cholesterol, and triglycerides. Liver, lung, and bronchoalveolar lavage contained less than or equal to control levels of phospholipids, cholesterol, and triglycerides. Percent of palmitate in the hepatic fatty acid profile was slightly increased in liver but not in lung. The source of the increased lipids in the serum is unknown.
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Abstract
The specific activities of palmitoyl-CoA synthetase, phospholipase A2, and lysophosphatidylcholine acyltransferase enzymes were low in the lungs of diabetic and hypophysectomized rats as compared to those found in the normal controls. Administration of triiodothyronine (T3), to the diabetic and hypophysectomized rats restored the normal activities of these enzymes. Stimulation of the enzyme activities were also observed when normal rats were injected with the above hormone. The enhancement of the enzyme activities was also found to be dependent on the dose and duration of the hormonal treatment. Optimum levels were achieved at a dose of about 100 micrograms/100 g body weight of T3, 3-4 days after the administration of this hormone. Actinomycin D or cycloheximide abolished the hormone-mediated stimulation of these enzymes in diabetic and hypophysectomized rats. Reduced rate of in vivo palmitoyl-CoA synthetase synthesis was observed in the lungs of diabetic and hypophysectomized animals. Administration of T3 stimulated the rate of synthesis of this enzyme indicating increasing synthesis of this enzyme and not of activation of the pre-existing inactive species. Reduced phospholipid contents, specially decreased amount of lecithin and dipalmitoyl lecithin (DPL) were observed in the lungs of the diabetic and hypophysectomized animals as compared to those in the normal animals. T3 also increased the lecithin and DPL content of the normal rat lungs. These results provide evidence for the involvement of the thyroid hormones in the control of the pulmonary surfactant. The results further suggest that T3 was capable of inducing the enzymes of the "deacylation-reacylation" pathway involved in palmitate incorporation into phosphatidylcholine thereby contributing to the stimulation of dipalmitoyl phosphatidylcholine biosynthesis.
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Reddy PV, Natarajan V, Schmid PC, Schmid HH. N-Acylation of dog heart ethanolamine phospholipids by transacylase activity. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 750:472-80. [PMID: 6824721 DOI: 10.1016/0005-2760(83)90187-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Radioactive N-acylethanolamine phospholipids were produced in dog heart homogenates incubated with acyl-labeled phosphatidylcholine in the presence of 5 mM Ca2+ and Triton X-100. 70-80% of the label in the N-acylethanolamine phospholipids was recovered in the N-acyl groups and most of the remainder was in the 1-O-acyl groups. Incubations with 1,2-dipalmitoylPC and 1-palmitoyl-2-linoleoylPC labeled in either the 1-O-acyl or 2-O-acyl moiety showed the predominant utilization of the acyl groups at the sn-1 position, indicating transacylation by phospholipase A1 (or lysophospholipase) activity. It is suggested that intramolecular transacylation from 1-O-acyl to N-acyl groups of phosphatidylethanolamine also occurred to some extent, thus providing a free primary hydroxy group as an additional acyl acceptor for the transacylation reaction.
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Okuyama H, Yamada K, Miyagawa T, Suzuki M, Prasad R, Lands WE. Enzymatic basis for the formation of pulmonary surfactant lipids by acyltransferase systems. Arch Biochem Biophys 1983; 221:99-107. [PMID: 6687523 DOI: 10.1016/0003-9861(83)90125-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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31
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Franson RC, Weir DL. Isolation and characterization of a membrane-associated, calcium-dependent phospholipase A2 from rabbit lung. Lung 1982; 160:275-84. [PMID: 7121065 DOI: 10.1007/bf02719301] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Ichikawa I, Yokoyama E. Effect of short-term exposure to ozone on the lecithin metabolism of rat lung. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 1982; 10:1005-15. [PMID: 7161832 DOI: 10.1080/15287398209530312] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The effect of short-term inhalation of ozone (O3) on the content and metabolism of phospholipids, particularly lecithin (PC), in rat lung was studied. The PC level increased slightly, but significantly, in the lung of rats exposed to 2 ppm O3 for 3 h. However, the PC level remained within the control level following the exposure to 2.5 and 5 ppm of O3 for 3 h, while the lysolecithin (LysoPC) content greatly increased. The incorporation of [32P]orthophosphate (32Pi) and [14C]palmitic acid into PC in the lung slices obtained from the animals tended to increase following the exposure to 2 ppm for 3 h, but decreased following the exposure to O3 above 2.5 ppm for 3 h. On the other hand, the radioactivity of 32Pi in LysoPC of lung from the rats exposed to O3 above 2.5 ppm was significantly greater than that from the control. Such changes in the content of PC or LysoPC and in the incorporation of labeled precursors into them may be explained, at least in part, by the combination of the presently and previously observed changes in the activities of enzymes participating in PC metabolism pathway as follows: (1) the significant stimulation in the activity of LysoPC acyltransferase (LysoPC ATF), which can transfer fatty acids onto LysoPC, for palmitic acid at an earlier stage of the exposure to O3 at 2 and 2.5 ppm; (2) the depression in the activities of this enzyme and another ATF-LysoPC-LysoPC ATF, which can synthesize one molecule of disaturated PC from two moles of saturated-LysoPC-by increasing the O3 exposure time; and (3) the stimulation in the phospholipase A2 activity in the lung of rats exposed to 2 ppm of O3 for 6 h.
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Chapter 9 Phospholipases. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0167-7306(08)60013-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Chapter 1 Phosphatidylserine, phosphatidylethanolamine and phosphatidylcholine. ACTA ACUST UNITED AC 1982. [DOI: 10.1016/s0167-7306(08)60005-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
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Van Heusden GP, Ruestow B, Van der Mast MA, Van den Bosch H. Synthesis of disaturated phosphatidylcholine by cholinephosphotransferase in rat lung microsomes. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 666:313-21. [PMID: 6275886 DOI: 10.1016/0005-2760(81)90289-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. Incubation of rat lung microsomes with cytidine diphospho[methyl-14C]choline resulted in synthesis of radioactively labeled phosphatidylcholine. 2. 10-15% of this phosphatidylcholine appeared to be disaturated species. In similar experiments with rat liver microsomes only 2-3% of the radioactivity was present in the disaturated species. 3. When de novo synthesis was blocked after 5 min by addition of Ca2+ no increase in the proportion of disaturated phosphatidylcholine was observed upon further incubation of lung microsomes. Under these conditions the enzymes involved in a remodeling mechanism, i.e. phospholipase A and acyl-CoA: lysophosphatidyl-choline acyltransferase, remain fully active. 4. Addition of diacylglycerols from egg phosphatidylcholine containing trace amounts of di[1-14C]palmitoyl glycerol resulted in direct incorporation of 14C label into phosphatidylcholine. The rate of phosphatidylcholine synthesis measured from incorporation of di[1-14C]palmitoyl glycerol equalled that observed with labeled CDP choline. 5. These results support the conclusion that disaturated phosphatidylcholine in lung can be formed by direct utilization of disaturated diacylglycerol and is not produced exclusively via remodelling of de novo synthesized unsaturated species.
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Abstract
The highly pulmonary concentration of 1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine (dipalmitoyllecithin) and its implication as an important component of lung surfactant have promoted investigation of phospholipid metabolism in the lung. This review will set the contents including recent informations for better understanding of phospholipid metabolism of the lung in normal state (physiological significances of lung phospholipids, characteristics of phospholipids in lung tissue and alveolar washing, biosynthetic pathways of dipalmitoyllecithin, etc.) as well as in toxic states (pulmonary oxygen toxicity, etc.) and in diseased states (idiopathic respiratory distress syndrome, pulmonary alveolar proteinosis, etc.) Since our main concern has been to clarify the most important route for supplying dipalmitoyllecithin, this review will be focused upon the various biosynthetic pathways leading to the formation of different molecular species of lecithin and their potential significance in the normal, toxic, and diseased lungs.
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von Wichert P, Temmesfeld M, Meyer W. Influence of septic shock upon phosphatidylcholine remodeling mechanism in rat lung. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 664:487-97. [PMID: 6791696 DOI: 10.1016/0005-2760(81)90127-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Septic shock in rats lead to pulmonary disorders associated with alterations of phospholipid metabolism. The ratio between phosphatidylcholine and lysophosphatidylcholine is lowered both in lung tissue and in pulmonary surfactant because enzymes of phosphatidylcholine remodeling mechanism are distinctly affected by septic shock. Specific activity of phospholipase A2 is enhanced 5-fold while specific activities of lysolecithin acyltransferase and lysolecithin : lysolecithin acyltransferase are only slightly increased or remain unchanged. Beyond that, palmitic acid content of lung tissue phosphatidylcholine is significantly reduced and replaced mainly by arachidonic acid. The release of this fatty acid by action of phospholipase A2 may lead via intermediates to the generation of potent mediators such as prostaglandins, thromboxane or slow-reacting substance.
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van Heusden GP, Noteborn HP, ven Den Bosch H. Selective utilization of palmitoyl lysophosphatidylcholine in this synthesis of disaturated phosphatidylcholine in rat lung: a combined in vitro and in vivo approach. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 664:49-60. [PMID: 7236698 DOI: 10.1016/0005-2760(81)90027-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
1. The acyl-CoA:lysophosphatidylcholine acyltransferase system in rat lung microsomes was found to utilize selectively 1-[1-14C]palmitoyl-sn-glycero-3-phosphocholine when compared with 1-[9,10-3H2]stearoyl-sn-glycero-3-phosphocholine. This result was found with either palmitoyl-CoA, linoleoyl-CoA or an equimolar mixture of these acyl donors and confirms recent data reported by Holub, Piekarski and Possmayer (Can. J. Biochem. 58 (1980) 434-439). 2. The selective utilization of palmitoyl lysophosphatidylcholine from a mixture of lysophosphatidylcholine species may cause an increased isotopic ratio in phosphatidylcholine when compared with that of total lysophosphatidylcholine. Thus, when rats were injected with a single doubly labelled species, i.e. 1-[9,10-3H2]palmitoyl-sn-glycero-3-phospho[methyl-14C]choline, the isotopic ratio in both total and disaturated phosphatidylcholine from lung was nearly identical to that of the injected substrate. This suggested a direct acylation by lung acyl-CoA:lysophosphatidylcholine acyltransferases. By contrast, when a mixture of 1-[9,10-3H2]palmitoyl-sn-glycero-3-phospho[methyl-14C]choline and 1-stearoyl-sn-glycero-3-phospho[methyl-14C]choline was injected, the 3H/14C ratio in disaturated lung phosphatidylcholine increased to about 1.4-fold that of the injected substrate. 3. These data indicate that increased isotopic ratios in disaturated phosphatidylcholine of lung tissue, after intravenous injection of lysophosphatidylcholine, do not necessarily point to the involvement of lysophosphatidylcholine:lysophosphatidylcholine transacylase in disaturated phosphatidylcholine formation.
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van Heusden GP, Reutelingsperger CP, van den Bosch H. Substrate specificity of lysophospholipase-transacylase from rat lung and its action on various physical forms of lysophosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 663:22-33. [PMID: 7011412 DOI: 10.1016/0005-2760(81)90191-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Lysophospholipase-transacylase (lysolecithin acylhydrolase, EC 3.1.1.5) from rat lung catalyzes the transfer of acyl groups from lysophosphatidylcholine to either water or another molecule of lysophosphatidylcholine. Studies on the substrate specificity of the purified enzyme showed that a phosphate group in the substrate is essential for enzymatic activity; monoacylglycerol is not hydrolyzed, nor does it serve as an acceptor of acyl groups. The influence of the acyl chain in lysophosphatidylcholine was investigated by using mixtures of differently labelled lysophosphatidylcholine species, or by studying the transfer of [1-14C]Palmitate from [1-14C]palmitoylpropane (1,3)diol-phosphocholine to various 1-acyl-sn-glycero-3-phosphocholines. Lysophosphatidylcholines with acyl chains comprised of ten or more C-atoms were found to serve as acyl acceptors. This finding was used to determine the action of the enzyme on 1-[1-14C]auroyl- and 1[1-14C]myristoyl-sn-glycero-3-phosphocholine both below and above the critical micelle concentration of the substrate. Monomeric substrate was effectively hydrolyzed, but the transacylase activity of the enzyme was only expressed when substrate micelles were present. Likewise, no transacylase activity was found when lysophosphatidylcholine was embedded in liposomal membranes prepared from lung total lipids. These findings, which persist with crude enzyme preparations (100 000 x g supernatant), are discussed in relation to the putative function of the lysophospholipase-transacylase in the synthesis of disaturated phosphatidylcholine in lung.
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van den Bosch H, Vianen GM, van Heusden GP. Lysophospholipase--transacylase from rat lung. Methods Enzymol 1981; 71 Pt C:513-21. [PMID: 7278668 DOI: 10.1016/0076-6879(81)71061-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Chakravarti DN, Chakravarti B, Chakrabarti P. Studies on phospholipase activities in Neurospora crassa mycelia. Lipids 1980; 15:830-7. [PMID: 6449646 DOI: 10.1007/bf02534373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Phospholipase A activity has been detected in mycelial homogenate of Neurospora crassa. A submycelial fraction, obtained by differential centrifugation containing the highest specific activity of phospholipase A has been shown to contain ca. 66% phospholipase A and 34% phospholipase A activity along with lysophospholipase and degergent-stimulated phospholipase D activity. Phospholipase A activity bound to N. crassa mycelia also has been observed.
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van Heusden G, Vianen G, van den Bosch H. Differentiation between acyl coenzyme A:lysophosphatidylcholine acyltransferase and lysophosphatidylcholine: lysophosphatidylcholine transacylase in the synthesis of dipalmitoylphosphatidylcholine in rat lung. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70563-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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44
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Synthesis of phosphatidylcholine and phosphatidylglycerol by alveolar type II cells in primary culture. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70755-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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45
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Batenburg JJ, Post M, Oldenborg V, Van Golde LM. The perfused isolated lung as a possible model for the study of lipid synthesis by type II cells in their natural environment. Exp Lung Res 1980; 1:57-65. [PMID: 6894426 DOI: 10.3109/01902148009057513] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The incorporation of radioactively labeled palmitate and acetate into total and disaturated phosphatidylcholines was studied in the perfused whole lung, in surfactant secreted during perfusion, and in isolated alveolar type II cells. Exogenously added palmitate was found to be incorporated preferentially into the 2-position of total and disaturated phosphatidylcholines in all cases. Acetate, when supplied at a high concentration, was incorporated preferentially into the 2-position in all cases. However, acetate supplied at a low concentration was incorporated preferentially into the 2-position in type II cells and in surfactant, but preferentially into the 1-position in the whole lung. The dissimilarity in incorporation of acetate between isolated type II cells and perfused whole lung and the similarity in this respect between isolated type II cells and surfactant indicate that the perfused isolated lung may only be a good model for studying the synthesis of surfactant components by the type II cells in their natural environment if the products of processes in type II cells are separated from products of other cells after the perfusion. Both in surfactant and in lavaged lung tissue, labeled palmitate and acetate incorporated mainly into the 2-position of phosphatidylglycerol. This indicates that remodeling reactions are involved in the synthesis of dipalmitoylphosphatidylglycerol.
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Wykle RL, Malone B, Blank ML, Snyder F. Biosynthesis of pulmonary surfactant: comparison of 1-palmitoyl-sn-glycero-3-phosphocholine and palmitate as precursors of dipalmitoyl-sn-glycero-3-phosphocholine in adenoma alveolar type II cells. Arch Biochem Biophys 1980; 199:526-37. [PMID: 6892673 DOI: 10.1016/0003-9861(80)90310-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Voelker D, Snyder F. Subcellular site and mechanism of synthesis of disaturated phosphatidylcholine in alveolar type II cell adenomas. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86938-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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48
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Jobe A. Kinetics of the in vivo labeling of the acyl groups of rabbit lung phosphatidylcholine and disaturated phosphatidylcholine. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 574:268-79. [PMID: 486512 DOI: 10.1016/0005-2760(79)90008-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The kinetics of labeling of lung phosphatidylcholine and disaturated phosphatidylcholine were studied for periods from 0.75--120 min following intravenous injection of radiolabeled palmitic acid and choline into 3-day-old rabbits. The labeled palmitic acid was cleared rapidly from plasma, and rapidly appeared with identical incorporation kinetics in both phosphatidylcholine and disaturated phosphatidylcholine. The 2-acyl positions of both phosphatidylcholine and disaturated phosphatidylcholine were labeled preferentially soon after [14C]palmitic acid injection. The specific activities of palmitic acid in the 2-acyl positions of phosphatidylcholine and disaturated phosphatidylcholine 0.75 min after injection of labeled palmitic acid were 3.4 and 1.9 times, respectively, the specific activities of palmitic acid in the 1-acyl positions. By 120 min the label had randomized between the 1-acyl and 2-acyl positions, and the kinetics of that randomization were defined for both phosphatidylcholine and disaturated phosphatidylcholine. Choline did not pulse label lung phosphatidylcholine or disaturated phosphatidylcholine. The choline label appeared with equal specific activities in both phosphatidylcholine and disaturated phosphatidylcholine. Thus no analysis of the de novo synthesized product via the CDP-choline pathway was possible.
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Nardone LL, Andrews SB. Cell line A549 as a model of the type II pneumocyte. Phospholipid biosynthesis from native and organometallic precursors. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 573:276-95. [PMID: 444551 DOI: 10.1016/0005-2760(79)90061-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
1. A549 is a continuous cell line derived from a human pulmonary adenocarcinoma. To evaluate the suitability of this cell line as a model of the type II pneumocyte, the morphology and the composition and biosynthesis of phosphatidylcholine was examined under control culture conditions and during fatty acid supplementation with palmitate. A number of the ultrastructural characteristics of A549 cells were similar to the in situ type II pneumocyte and were unchanged by fatty acid supplementation. The phospholipid composition of the cell line was similar to that of primary isolates of type II cells in total phosphatidylcholine, disaturated phosphatidylcholine, and palmitate and saturated fatty acid. Phospholipid biosynthetic results were also consistent with those reported for isolated type II cell models. These included: (i) the pattern of incorporation of choline, palmitate and acetate into phosphatidylcholines; (ii) the effect of palmitate supplementation, which resulted in stimulation of the rate of phosphatidylcholine biosynthesis and in increased percentage of labeled precursor in disaturated phosphatidylcholine; and (iii) the preferential synthesis from labeled choline and palmitate of a highly disaturated phosphatidylcholine in short-term incubations. 2. The incorporation of an organometallic palmitate analog, 12,12-dimethyl-12-stannahexadecanoate, into A549 cell lipids was examined and compared to that of palmitate. These date demonstrate for the first time the incorporation of an organometallic substrate into the phospholipids of a mammalian cell line. This analog substitutes selectively for the native fatty acid at a rate similar to that of the native fatty acid with no cytotoxic effects. The organotin probe, coupled with spectroscopic detection and electron microscopy, may be useful for examining ultrastructural aspects of phospholipid synthesis, translocation and assembly.
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Longmore WJ, Oldenborg V, van Golde LM. Phospholipase A2 in rat-lung microsomes: substrate specificity towards endogenous phosphatidylcholines. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 572:452-60. [PMID: 35234 DOI: 10.1016/0005-2760(79)90152-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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