Intracellular transport of phosphatidic acid and phosphatidylcholine into lipid bodies: use of fluorescent lipids to study lipid-body formation in an oleaginous fungus

2000 ◽  
Vol 28 (6) ◽  
pp. 723-725
Author(s):  
Y. Kamisaka ◽  
N. Noda
Keyword(s):  
Phosphatidic Acid ◽  
Temperature Dependence ◽  
Intracellular Transport ◽  
Lipid Body ◽  
Lipid Transport ◽  
Lipid Bodies ◽  
Transport Pathways ◽  
Body Formation ◽  
Oleaginous Fungus ◽  
Fluorescent Lipids

Fluorescent phosphatidic acid and phosphatidylcholine were used to characterize lipid-transport pathways into lipid bodies in an oleaginous fungus, Mortierella ramanniana var. angulispora. Several characteristics of the lipid transport such as temperature dependence and ATP dependence were evaluated. The transport depicted by these fluorescent lipids was consistent with metabolism of radiolabelled lipids, indicating that fluorescent lipids are useful to study lipid-body formation in this fungus. The results dissect lipid transport of phosphatidic acid and phosphatidylcholine into lipid bodies and reveal regulatory steps for lipidbody formation in this fungus.

scholarly journals Cytoplasmic lipid bodies of neutrophils: formation induced by cis-unsaturated fatty acids and mediated by protein kinase C.

1991 ◽  
Vol 113 (1) ◽  
pp. 137-146 ◽  
Author(s):  
P F Weller ◽  
S W Ryeom ◽  
S T Picard ◽  
S J Ackerman ◽  
A M Dvorak
Keyword(s):  
Fatty Acids ◽  
Protein Kinase C ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Unsaturated Fatty Acids ◽  
Lipid Body ◽  
Lipid Bodies ◽  
Myristate Acetate ◽  
Body Formation ◽  
Kinase C

Lipid bodies, nonmembrane-bound cytoplasmic inclusions, serve as repositories of esterified arachidonate and are increased in cells associated with inflammatory reactions. We have evaluated stimuli and mechanisms responsible for lipid body formation within human polymorphonuclear leukocytes (PMNs). Arachidonic acid and oleic acid stimulated dose-dependent formation of lipid bodies over 0.5-1 h. Other C20 and C18 fatty acids were less active and demonstrated rank orders as follows: cis-unsaturated fatty acids were much more active than trans-fatty acids, and activity diminished with decreasing numbers of double bonds. Lipid bodies elicited in vitro with cis-fatty acids were ultrastructurally identical to lipid bodies present in PMNs in vivo. Lipid body induction was not because of fatty acid-elicited oxidants or fatty acid-induced ATP depletion. Cis-fatty acid-induced activation of protein kinase C (PKC) was involved in lipid body formation as evidenced by the capacity of other PKC activators, 1-oleoyl-2-acetyl-glycerol and two active phorbol esters, phorbol myristate acetate, and phorbol 12,13 dibutyrate, but not an inactive phorbol, to induce lipid body formation. The PKC inhibitor, 1-O-hexadecyl-2-O-methyl-glycerol, inhibited PMN lipid body formation induced by oleic and arachidonic acids and by 1-oleoyl-2-acetyl-glycerol and phorbol myristate acetate. Other PKC inhibitors (staurosporine, H-7) also inhibited lipid body formation. Formation of lipid bodies in PMNs is a specific cellular response, stimulated by cis-fatty acids and diglycerides and apparently mediated by PKC, which results in the mobilization and deposition of lipids within discrete, ultrastructurally defined cytoplasmic domains.

scholarly journals Mechanisms of platelet-activating factor-induced lipid body formation: requisite roles for 5-lipoxygenase and de novo protein synthesis in the compartmentalization of neutrophil lipids.

1996 ◽  
Vol 183 (4) ◽  
pp. 1515-1525 ◽  
Author(s):  
P T Bozza ◽  
J L Payne ◽  
J L Goulet ◽  
P F Weller
Keyword(s):  
Actinomycin D ◽  
Platelet Activating Factor ◽  
Lipid Body ◽  
Lipid Bodies ◽  
Wild Type ◽  
Body Formation ◽  
Paf Receptor ◽  
Deficient Mice ◽  
Web 2086

Lipid bodies, lipid rich cytoplasmic inclusions, are characteristically abundant in vivo in leukocytes associated with inflammation. Because lipid bodies are potential reservoirs of esterified arachidonate and sites at which eicosanoid-forming enzymes may localize, we evaluated mechanisms of lipid body formation in neutrophils (PMN). Among receptor-mediated agonists, platelet activating factor (PAF), but not C5a, formyl-methyl-phenylalanine, interleukin 8, or leukotriene (LT) B4, induced the rapid formation of lipid bodies in PMN. This action of PAF was receptor mediated, as it was dose dependently inhibited by the PAF receptor antagonist WEB 2086 and blocked by pertussis toxin. Lipid body induction by PAF required 5-lipoxygenase (LO) activity and was inhibited by the 5-lipoxygenase-activating protein antagonist MK 886 and the 5-LO inhibitor zileuton, but not by cyclooxygenase inhibitors. Corroborating the dependency of PAF-induced lipid body formation on 5-LO, PMN and macrophages from wild-type mice, but not from 5-LO genetically deficient mice, formed lipid bodies on exposure to PAF both in vitro and in vivo within the pleural cavity. The 5-LO product inducing lipid body formation was not LTB4 but was 5(S)-hydroxyeicosatetraenoic acid [5(S)-HETE], which was active at 10-fold lower concentrations than PAF and was also inhibited by pertussis toxin but not by zileuton or WEB 2086. Furthermore, 5-HETE was equally effective in inducing lipid body formation in both wild-type and 5-LO genetically deficient mice. Both PAF- and 5(S)-HETE-induced lipid body formation were inhibited by protein kinase C (PKC) inhibitors staurosporine and chelerythrine, the phospholipase C (PLC) inhibitors D609 and U-73122, and by actinomycin D and cycloheximide. Prior stimulation of human PMN with PAF to form lipid bodies enhanced eicosanoid production in response to submaximal stimulation with the calcium ionophore A23187; and the levels of both prostaglandin (PG) E2 and LTB4 correlated with the number of lipid bodies. Furthermore, pretreatment of cells with actinomycin D or cycloheximide inhibited not only the induction of lipid body formation by PAF, but also the PAF-induced "priming" for enhanced PGE2 and LTB4 in PMN. Thus, the compartmentalization of lipids to form lipid bodies in PMN is dependent on specific cellular responses that can be PAF receptor mediated, involves signaling through 5-LO to form 5-HETE and then through PKC and PLC, and requires new protein synthesis. Since increases in lipid body numbers correlated with priming for enhanced PGE2 and LTB4 production in PMN, the induction of lipid bodies may have a role in the formation of eicosanoid mediators by leukocytes involved in inflammation.

scholarly journals Leptin Induces Macrophage Lipid Body Formation by a Phosphatidylinositol 3-Kinase- and Mammalian Target of Rapamycin-dependent Mechanism

2007 ◽  
Vol 283 (4) ◽  
pp. 2203-2210 ◽  
Author(s):  
Clarissa M. Maya-Monteiro ◽  
Patricia E. Almeida ◽  
Heloisa D'Ávila ◽  
Aline S. Martins ◽  
Ana Paula Rezende ◽  
...  
Keyword(s):  
Mammalian Target Of Rapamycin ◽  
Lipid Body ◽  
Target Of Rapamycin ◽  
Phosphatidylinositol 3 Kinase ◽  
Body Formation ◽  
Dependent Mechanism ◽  
Phosphatidylinositol 3

scholarly journals The Rhodococcus opacus PD630 Heparin-Binding Hemagglutinin Homolog TadA Mediates Lipid Body Formation

2010 ◽  
Vol 76 (21) ◽  
pp. 7217-7225 ◽  
Author(s):  
Daniel P. MacEachran ◽  
M. E. Prophete ◽  
A. J. Sinskey
Keyword(s):  
Kinetic Studies ◽  
Lipid Body ◽  
Dry Weight ◽  
Rhodococcus Opacus ◽  
Lipid Bodies ◽  
Heparin Binding ◽  
Tag Biosynthesis ◽  
Tag Accumulation

ABSTRACT Generally, prokaryotes store carbon as polyhydroxyalkanoate, starch, or glycogen. The Gram-positive actinomycete Rhodococcus opacus strain PD630 is noteworthy in that it stores carbon in the form of triacylglycerol (TAG). Several studies have demonstrated that R. opacus PD630 can accumulate up to 76% of its cell dry weight as TAG when grown under nitrogen-limiting conditions. While this process is well studied, the underlying molecular and biochemical mechanisms leading to TAG biosynthesis and subsequent storage are poorly understood. We designed a high-throughput genetic screening to identify genes and their products required for TAG biosynthesis and storage in R. opacus PD630. We identified a gene predicted to encode a putative heparin-binding hemagglutinin homolog, which we have termed tadA (triacylglycerol accumulation deficient), as being important for TAG accumulation. Kinetic studies of TAG accumulation in both the wild-type (WT) and mutant strains demonstrated that the tadA mutant accumulates 30 to 40% less TAG than the parental strain (WT). We observed that lipid bodies formed by the mutant strain were of a different size and shape than those of the WT. Characterization of TadA demonstrated that the protein is capable of binding heparin and of agglutinating purified lipid bodies. Finally, we observed that the TadA protein localizes to lipid bodies in R. opacus PD630 both in vivo and in vitro. Based on these data, we hypothesize that the TadA protein acts to aggregate small lipid bodies, found in cells during early stages of lipid storage, into larger lipid bodies and thus plays a key role in lipid body maturation in R. opacus PD630.

scholarly journals PPAR-γ activation by Tityus serrulatus venom regulates lipid body formation and lipid mediator production

Toxicon ◽  
2015 ◽  
Vol 93 ◽  
pp. 90-97 ◽  
Author(s):  
Karina Furlani Zoccal ◽  
Francisco Wanderley Garcia Paula-Silva ◽  
Claudia da Silva Bitencourt ◽  
Carlos Artério Sorgi ◽  
Karla de Castro Figueiredo Bordon ◽  
...  
Keyword(s):  
Lipid Body ◽  
Lipid Mediator ◽  
Body Formation ◽  
Ppar Γ ◽  
Tityus Serrulatus ◽  
Tityus Serrulatus Venom

scholarly journals Hydrophobicity drives the systemic distribution of lipid-conjugated siRNAs via lipid transport pathways

2018 ◽  
Author(s):  
Maire F. Osborn ◽  
Andrew H. Coles ◽  
Annabelle Biscans ◽  
Reka A. Haraszti ◽  
Loic Roux ◽  
...  
Keyword(s):  
Sirna Delivery ◽  
Lipid Transport ◽  
Small Interfering Rnas ◽  
Transport Pathways ◽  
Efficient Delivery ◽  
Systemic Distribution ◽  
Lipoprotein Binding ◽  
The Impact ◽  
Plasma Half Life

AbstractEfficient delivery of therapeutic RNA is the fundamental obstacle preventing its clinical utility. Lipid conjugation improves plasma half-life, tissue accumulation, and cellular uptake of small interfering RNAs (siRNAs). However, the impact of conjugate structure and hydrophobicity on siRNA pharmacokinetics is unclear, impeding the design of clinically relevant lipid-siRNAs. Using a panel of biologically-occurring lipids, we show that lipid conjugation modulates siRNA hydrophobicity and governs spontaneous partitioning into distinct plasma lipoprotein classes in vivo. Lipoprotein binding influences siRNA distribution by delaying renal excretion and promoting uptake into lipoprotein receptor-enriched tissues. Lipid-siRNAs elicit mRNA silencing without causing toxicity in a tissue-specific manner. Lipid-siRNA internalization occurs independently of lipoprotein endocytosis, and is mediated by siRNA phosphorothioate modifications. Although biomimetic lipoprotein nanoparticles have been considered for the enhancement of siRNA delivery, our findings suggest that hydrophobic modifications can be leveraged to incorporate therapeutic siRNA into endogenous lipid transport pathways without the requirement for synthetic formulation.

The Oxygen-Dependent Modification of Triacylglycerols and Phospholipids, the Different Way of Initiating Lipid Body Mobilization

1997 ◽  
Vol 52 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Helmut Kindi
Keyword(s):  
Cucumis Sativus ◽  
Intracellular Localization ◽  
Lipid Body ◽  
Chemical Mechanism ◽  
Lipid Bodies ◽  
Important Process ◽  
Lipid Mobilization ◽  
Phospholipid Monolayer ◽  
Dependent Modification ◽  
Plant Seedlings

For plant seedlings dependent on the breakdown of lipid reserves for gluconeogenesis the onset of lipid mobilization is a critically important process. Until recently, knowledge about the chemical mechanism of the initial breakdown steps has been limited, because the lipolytic activities, characterized by the intracellular localization and the type of substrate, have not always been found. As seedlings that depend on the reserves in lipid bodies may differ in morphology and biochemistry, it is likely that more than one pathway exists. Recent studies with cucumber (Cucumis sativus) cotyledons have shown that a lipid body-associated lipoxygenase, and an O2-dependent reaction, initiate both the destabilization of the phospholipid monolayer and the breakdown of triglycerides. Both types of reactions rely on the particular properties of a lipoxygenase isoform exclusively present in lipid bodies.

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