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O'Donnell VB. New appreciation for an old pathway: the Lands Cycle moves into new arenas in health and disease. Biochem Soc Trans 2022; 50:1-11. [PMID: 35225335 PMCID: PMC9022965 DOI: 10.1042/bst20210579] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 02/15/2022] [Accepted: 02/15/2022] [Indexed: 02/08/2023]
Abstract
The Lands Pathway is a fundamental biochemical process named for its discovery by William EM Lands and revealed in a series of seminal papers published in the Journal of Biological Chemistry between 1958-65. It describes the selective placement in phospholipids of acyl chains, by phospholipid acyltransferases. This pathway has formed a core component of our knowledge of phospholipid and also diglyceride metabolism in mammalian tissues for over 60 years now. Our understanding of how the Lands pathways are enzymatically mediated via large families of related gene products that display both substrate and tissue specificity has grown exponentially since. Recent studies building on this are starting to reveal key roles for the Lands pathway in specific scenarios, in particular inflammation, immunity and inflammation. This review will cover the Lands cycle from historical perspectives first, then present new information on how this important cycle forms a central regulatory node connecting fatty acyl and phospholipid metabolism and how its altered regulation may present new opportunities for therapeutic intervention in human disease.
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Affiliation(s)
- Valerie B. O'Donnell
- Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff CF14 4SN, U.K
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dos Santos Seckler H, Fornelli L, Mutharasan RK, Thaxton CS, Fellers R, Daviglus M, Sniderman A, Rader D, Kelleher NL, Lloyd-Jones DM, Compton PD, Wilkins JT. A Targeted, Differential Top-Down Proteomic Methodology for Comparison of ApoA-I Proteoforms in Individuals with High and Low HDL Efflux Capacity. J Proteome Res 2018; 17:2156-2164. [PMID: 29649363 PMCID: PMC6162093 DOI: 10.1021/acs.jproteome.8b00100] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Top-down proteomics (TDP) allows precise determination/characterization of the different proteoforms derived from the expression of a single gene. In this study, we targeted apolipoprotein A-I (ApoA-I), a mediator of high-density-lipoprotein cholesterol efflux (HDL-E), which is inversely associated with coronary heart disease risk. Absolute ApoA-I concentration and allelic variation only partially explain interindividual HDL-E variation. Therefore, we hypothesize that differences in HDL-E are associated with the abundances of different ApoA-I proteoforms. Here, we present a targeted TDP methodology to characterize ApoA-I proteoforms in serum samples and compare their abundances between individuals. We characterized 18 ApoA-I proteoforms using selected-ion monitoring coupled to electron-transfer dissociation mass spectrometry. We then compared the abundances of these proteoforms between two groups of four participants, representing the individuals with highest and lowest HDL-E values within the Chicago Healthy Aging Study ( n = 420). Six proteoforms showed significantly ( p < 0.0005) higher intensity in high HDL-E individuals: canonical ApoA-I [fold difference (fd) = 1.17], carboxymethylated ApoA-I (fd = 1.24) and, with highest difference, four fatty acylated forms: palmitoylated (fd = 2.16), oleoylated (fd = 2.08), arachidonoylated (fd = 2.31) and one bearing two modifications: palmitoylation and truncation (fd = 2.13). These results demonstrate translational potential for targeted TDP in revealing, with high sensitivity, associations between interindividual proteoform variation and physiological differences underlying disease risk.
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Affiliation(s)
- Henrique dos Santos Seckler
- Departments of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Luca Fornelli
- Departments of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - R. Kannan Mutharasan
- Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Chicago, IL, USA; The Department of Medicine (Cardiology), Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - C. Shad Thaxton
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
- International Institute for Nanotechnology (IIN), Northwestern University, Evanston, IL, USA
- Feinberg School of Medicine, Department of Urology, Northwestern University, Chicago, IL, USA
| | - Ryan Fellers
- Departments of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA
| | - Martha Daviglus
- Northwestern University Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL, USA
- University of Illinois at Chicago, Institute for Minority Health Research, Chicago, IL, USA
| | - Allan Sniderman
- Royal Victoria Hospital–McGill University Health Centre, Montreal, QC, Canada
| | - Daniel Rader
- Department of Medicine and Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Neil L. Kelleher
- Departments of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Donald M. Lloyd-Jones
- Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Chicago, IL, USA; The Department of Medicine (Cardiology), Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Northwestern University Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL, USA
| | - Philip D. Compton
- Departments of Chemistry and Molecular Biosciences and the Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - John T. Wilkins
- Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Chicago, IL, USA; The Department of Medicine (Cardiology), Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Northwestern University Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL, USA
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Martin SA, Gijón MA, Voelker DR, Murphy RC. Measurement of lysophospholipid acyltransferase activities using substrate competition. J Lipid Res 2014; 55:782-91. [PMID: 24563510 DOI: 10.1194/jlr.d044636] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Lysophospholipid acyltransferases (LPATs) incorporate fatty acyl chains into phospholipids via a CoA-dependent mechanism and are important in remodeling phospholipids to generate the molecular species of phospholipids found in cells. These enzymes use one lysophospholipid and one acyl-CoA ester as substrates. Traditional enzyme activity assays engage a single substrate pair, whereas in vivo multiple molecular species exist. We describe here an alternative biochemical assay that provides a mixture of substrates presented to the microsomal extracts. Microsomal preparations from RAW 264.7 cells were used to compare traditional LPAT assays with data obtained using a dual substrate choice assay using six different lysophospholipids and eight different acyl-CoA esters. The complex mixture of newly synthesized phospholipid products was analyzed using LC-MS/MS. Both types of assays provided similar results, but the dual choice assay provided information about multiple fatty acyl chain incorporation into various phospholipid classes in a single reaction. Engineered suppression of LPCAT3 activity in RAW 264.7 cells was easily detected by the dual choice method. These findings demonstrate that this assay is both specific and sensitive and that it provides much richer biochemical detail than traditional assays.
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Affiliation(s)
- Sarah A Martin
- Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045
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Jackson SK, Abate W, Tonks AJ. Lysophospholipid acyltransferases: novel potential regulators of the inflammatory response and target for new drug discovery. Pharmacol Ther 2008; 119:104-14. [PMID: 18538854 DOI: 10.1016/j.pharmthera.2008.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Molecular and biochemical analyses of membrane phospholipids have revealed that, in addition to their physico-chemical properties, the metabolites of phospholipids play a crucial role in the recognition, signalling and responses of cells to a variety of stimuli. Such responses are mediated in large part by the removal and/or addition of different acyl chains to provide different phospholipid molecular species. The reacylation reactions, catalysed by specific acyltransferases control phospholipid composition and the availability of the important mediators free arachidonic acid and lysophospholipids. Lysophospholipid acyltransferases are therefore key control points for cellular responses to a variety of stimuli including inflammation. Regulation or manipulation of lysophospholipid acyltransferases may thus provide important mechanisms for novel anti-inflammatory therapies. This review will highlight mammalian lysophospholipid acyltransferases with particular reference to the potential role of lysophosphatidylcholine acyltransferase and its substrates in sepsis and other inflammatory conditions and as a potential target for novel anti-inflammatory therapies.
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Affiliation(s)
- Simon K Jackson
- Centre for Research in Biomedicine, Faculty of Health and Life Sciences, Frenchay Campus, University of the West of England, Bristol, UK.
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Das S, Stevens T, Castillo C, Villasenõr A, Arredondo H, Reddy K. Lipid metabolism in mucous-dwelling amitochondriate protozoa. Int J Parasitol 2002; 32:655-75. [PMID: 12062485 DOI: 10.1016/s0020-7519(02)00006-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Entamoeba, Giardia, and trichomonads are the prominent members of a group known as 'mucosal parasites'. While Entamoeba and Giardia trophozoites colonise the small intestine, trichomonads inhabit the genitourinary tracts of humans and animals. These protozoa lack mitochondria, well-developed Golgi complexes, and other organelles typical of higher eukaryotes. Nonetheless, they have developed unique metabolic pathways that allow them to survive and multiply in the small intestine and reproductive tracts by scavenging nutrients from the host. Various investigators have shown that these protozoa are unable to synthesise the majority of their own lipids and cholesterol de novo; rather, they depend mostly on supplies from outside sources. Therefore, questions of how they transport and utilise exogenous lipids for metabolic purposes are extremely important. There is evidence suggesting that these parasites can take up the lipids and cholesterol they need from lipoprotein particles present in the host and/or in the growth medium. Studies also support the idea that individual lipid and fatty acid molecules can be transported without the help of lipoproteins. Exogenous phospholipids have been shown to undergo fatty acid remodelling (by deacylation/reacylation reactions), which allows these protozoa to alter lipids, bypassing the synthesis of entirely new phospholipid molecules. In addition, many of these amitochondriates are, however, capable of elongating/desaturating long-chain fatty acids, and assembling novel glycophospholipid molecules. In this review, progress in various aspects of lipid research on these organisms is discussed. Attempts are also made to identify steps of lipid metabolic pathways that can be used to develop chemotherapeutic agents against these and other mucosal parasites.
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Affiliation(s)
- Siddhartha Das
- Department of Biological Sciences, University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968-0519, USA.
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Kerkhoff C, Trümbach B, Gehring L, Habben K, Schmitz G, Kaever V. Solubilization, partial purification and photolabeling of the integral membrane protein lysophospholipid:acyl-CoA acyltransferase (LAT). EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:6339-45. [PMID: 11029575 DOI: 10.1046/j.1432-1327.2000.01724.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the present study, we defined experimental conditions that allowed the extraction of the integral membrane protein lysophospholipid:acyl-CoA acyltransferase (LAT, EC 2.3.1.23) from membranes while maintaining the full enzyme activity using the nonionic detergent n-octyl glucopyranoside (OGP) and solutions of high ionic strength. We found that the optimal OGP concentration depended on the ionic strength of the solubilization buffer. Fluorescence measurements with 1,6-diphenyl-1,3,5-hexatriene indicated that the critical micellar concentration (CMC) of OGP decreased with increasing salt concentrations. Analogous studies revealed that the zwitterionic detergent Chaps was ineffective in extracting LAT from membranes in the absence of salt, whereas its solubilization efficiency increased with increasing salt concentrations. Detailed lipid analysis of the different protein/lipid/detergent mixed micelles showed that the protein/lipid/OGP mixed micelles were relatively enriched with sphingomyelin (SPM) compared to protein/lipid/Chaps mixed micelles, indicating that the differences in the solubilization efficiency may be due to the ability to extract more SPM from membranes. When the protein/lipid/OGP mixed micelles were dissociated into protein/detergent and lipid/detergent complexes by the addition of increasing Chaps concentrations, one-tenth of the LAT enzyme activity was preserved making the enzyme accessible to protein purification. Analysis by native PAGE revealed that in the presence of excess Chaps a high molecular mass protein complex migrated into the gel which could be photolabeled by 125I-labelled-18-(4'-azido-2'-hydroxybenzoylamino)-oleyl-CoA. This fatty acid analogue has been shown to be a competitive inhibitor of LAT enzyme activity in the dark, and an irreversible inhibitor after photolysis. Therefore, this protein complex is assumed to contain the LAT enzyme.
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Affiliation(s)
- C Kerkhoff
- Institute of Pharmacology, Medical School Hannover, Germany
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