scholarly journals Toxoplasma LIPIN is essential in channeling host lipid fluxes through membrane biogenesis and lipid storage

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sheena Dass ◽  
Serena Shunmugam ◽  
Laurence Berry ◽  
Christophe-Sebastien Arnold ◽  
Nicholas J. Katris ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
De Novo ◽  
Lipid Synthesis ◽  
Parasite Development ◽  
Membrane Biogenesis ◽  
Membrane Phospholipids ◽  
Phosphatidic Acid Phosphatase ◽  
Intracellular Parasites ◽  
Parasite Survival

AbstractApicomplexa are obligate intracellular parasites responsible for major human diseases. Their intracellular survival relies on intense lipid synthesis, which fuels membrane biogenesis. Parasite lipids are generated as an essential combination of fatty acids scavenged from the host and de novo synthesized within the parasite apicoplast. The molecular and metabolic mechanisms allowing regulation and channeling of these fatty acid fluxes for intracellular parasite survival are currently unknown. Here, we identify an essential phosphatidic acid phosphatase in Toxoplasma gondii, TgLIPIN, as the central metabolic nexus responsible for controlled lipid synthesis sustaining parasite development. Lipidomics reveal that TgLIPIN controls the synthesis of diacylglycerol and levels of phosphatidic acid that regulates the fine balance of lipids between storage and membrane biogenesis. Using fluxomic approaches, we uncover the first parasite host-scavenged lipidome and show that TgLIPIN prevents parasite death by ‘lipotoxicity’ through effective channeling of host-scavenged fatty acids to storage triacylglycerols and membrane phospholipids.

Regulation Of The Fatty Acid Composition Of Platelet Phospholipids

1981 ◽  
Author(s):  
M L McKean ◽  
J B Smith ◽  
M J Silver
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
De Novo ◽  
Membrane Phospholipids ◽  
De Novo Biosynthesis ◽  
Coa Transferase

The fatty acid composition of cell membrane phospholipids does not remain constant after de novo biosynthesis, but undergoes continual remodelling. One of the major routes for remodelling probably includes the deacylation-reacylation steps of the Lands Pathway. This has been shown to be important for the incorporation of long chain, polyunsaturated fatty acids into phospholipids by liver and brain. An understanding of the mechanisms involved in these processes in platelets is especially important in light of the large stores of arachidonic acid (AA) in platelet phospholipids and the role of AA in hemostasis and thrombosis. Previous results from this laboratory have shown that the turnover of radioactive AA, 8,11,14-eicosatrienoic and 5,8,11,14,17-eicosapentaenoic acids in the phospholipids of resting platelets is more rapid than the turnover of radioactive C16 and C18 saturated and unsaturated fatty acids. However, little is known about how fatty acids, especially AA and its homologues, are incorporated into platelet phospholipids during de novo biosynthesis or how they are exchanged during remodelling.At least three enzymes are involved in the deacylation- reacylation of phospholipids: phospholipase A2; acyl CoA synthetase; and acyl CoA transferase. We have studied acyl CoA transferase and have found considerable activity in human platelet membranes. Experiments are in progress to determine the substrate specificity and other properties of this enzyme.

scholarly journals Hexadecenoic Fatty Acid Positional Isomers and De Novo PUFA Synthesis in Colon Cancer Cells

2019 ◽  
Vol 20 (4) ◽  
pp. 832 ◽  
Author(s):  
Roberta Scanferlato ◽  
Massimo Bortolotti ◽  
Anna Sansone ◽  
Chryssostomos Chatgilialoglu ◽  
Letizia Polito ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cancer Cells ◽  
De Novo ◽  
Fluorescent Microscopy ◽  
Positional Isomers ◽  
Membrane Phospholipids ◽  
Two Photon ◽  
Palmitic Acids ◽  
Delta 6 Desaturase

Palmitic acid metabolism involves delta-9 and delta-6 desaturase enzymes forming palmitoleic acid (9cis-16:1; n-7 series) and sapienic acid (6cis-16:1; n-10 series), respectively. The corresponding biological consequences and lipidomic research on these positional monounsaturated fatty acid (MUFA) isomers are under development. Furthermore, sapienic acid can bring to the de novo synthesis of the n-10 polyunsaturated fatty acid (PUFA) sebaleic acid (5cis,8cis-18:2), but such transformations in cancer cells are not known. The model of Caco-2 cell line was used to monitor sapienic acid supplementation (150 and 300 μM) and provide evidence of the formation of n-10 fatty acids as well as their incorporation at levels of membrane phospholipids and triglycerides. Comparison with palmitoleic and palmitic acids evidenced that lipid remodelling was influenced by the type of fatty acid and positional isomer, with an increase of 8cis-18:1, n-10 PUFA and a decrease of saturated fats in case of sapienic acid. Cholesteryl esters were formed only in cases with sapienic acid. Sapienic acid was the less toxic among the tested fatty acids, showing the highest EC50s and inducing death only in 75% of cells at the highest concentration tested. Two-photon fluorescent microscopy with Laurdan as a fluorescent dye provided information on membrane fluidity, highlighting that sapienic acid increases the distribution of fluid regions, probably connected with the formation of 8cis-18:1 and the n-10 PUFA in cell lipidome. Our results bring evidence for MUFA positional isomers and de novo PUFA synthesis for developing lipidomic analysis and cancer research.

scholarly journals Fluxes through the prokaryotic and eukaryotic pathways of lipid synthesis in the ‘16:3’ plant Arabidopsis thaliana

1986 ◽  
Vol 235 (1) ◽  
pp. 25-31 ◽  
Author(s):  
J Browse ◽  
N Warwick ◽  
C R Somerville ◽  
C R Slack
Keyword(s):  
Fatty Acids ◽  
Arabidopsis Thaliana ◽  
Fatty Acid ◽  
De Novo ◽  
Saturated Fatty Acids ◽  
Lipid Synthesis ◽  
Chloroplast Envelope ◽  
Large Contribution ◽  
Acetate Incorporation ◽  
Lipid Molecule

The kinetics of [1-14C]acetate incorporation in Arabidopsis thaliana L. (Heyn) showed almost equal labelling of phosphatidylcholine (PC) and diacylgalactosylglycerol (DGG) at early times and the transfer of radioactivity from PC to DGG and diacyldigalactosylglycerol (DDG) at longer times. These kinetics demonstrated the parallel operation of the prokaryotic and eukaryotic pathways of lipid synthesis [Roughan & Slack (1982) Annu. Rev. Plant Physiol. 33, 97-132] in this tissue. At 2 h after the application of [1-14C]acetate, more than 85% of the radioactivity at the sn-2 position of each chloroplast lipid was in 16-carbon fatty acids. However, after 60 h, molecular species containing labelled C18 fatty acids at position sn-2 and presumably derived from microsomal PC made a large contribution (20-70%) to each chloroplast lipid except phosphatidylglycerol. These findings are consistent with the contention that the chain length of the fatty acid at the sn-2 position of glycerol is an accurate predictor of whether a particular lipid molecule has been synthesized by the prokaryotic or eukaryotic pathway. At 30 min after the start of [1-14C]acetate labelling, only 12.3% of the radioactivity in PC was in saturated fatty acids, but the proportion increased steadily to 24.3% after 142 h. It is suggested that steps involved in the conversion of PC to chloroplast lipids on the eukaryotic pathway discriminate against palmitate-containing species. The step involved does not appear to be transfer of PC to the chloroplast because extrachloroplastic and chloroplast membranes purified from Arabidopsis mesophyll protoplasts each contained PC with a fatty acid composition similar to that of the same lipid from leaves. Positional analysis of unlabelled lipids, together with the information summarized above, is used to construct a quantitative scheme of the fluxes through the prokaryotic and eukaryotic pathways during lipid synthesis in Arabidopsis. This scheme shows that 38% of the fatty acids synthesized de novo in the chloroplast enter the prokaryotic pathway in the chloroplast envelope. Of the 62% which are exported as acyl-CoA species to enter the eukaryotic pathway, 56% (34% of the total) are returned to complete synthesis of the chloroplast's complement of glycerolipids.

scholarly journals Cholesterol dynamics are essential for the growth and development of Plasmodium falciparum within the erythrocyte

2021 ◽  
Author(s):  
Avantika I. Ahiya ◽  
Suyash Bhatnagar ◽  
Joanne Morrisey ◽  
Josh R. Beck ◽  
Akhil B. Vaidya
Keyword(s):  
Infected Erythrocyte ◽  
De Novo ◽  
Cholesterol Content ◽  
Cholesterol Homeostasis ◽  
Parasite Development ◽  
Trophozoite Stage ◽  
Parasite Survival ◽  
Erythrocytic Cycle ◽  
Erythrocyte Plasma Membrane ◽  
Rapid Expulsion

AbstractPlasmodium spp. lack de novo cholesterol synthetic pathways and can only scavenge it from their host erythrocyte. Here we report that depletion of cholesterol from the erythrocyte plasma membrane by methyl-β-cyclodextrin (MBCD) has dramatic consequences. The removal of cholesterol results in invasion defects as well as inhibition of parasite development through the intra-erythrocytic cycle. These defects could be rescued by reconstitution with cholesterol and desmosterol but not with epicholesterol. By using live microscopy of fluorescently tagged trophozoite stage parasites, we detected rapid expulsion of the parasites from erythrocyte when exposed to MBCD for just 30 mins. Strikingly, the parasites transition from being intra-erythrocytic to extracellular within 10 seconds and do so without rupturing the erythrocyte membrane. These extruded parasites were still surrounded by the parasitophorous vacuolar membrane (PVM) and remained tethered to the erythrocyte. Electron microscopy revealed that although extracellular parasites retained their PVM, it was heavily compromised. Treatment with antimalarials that disrupt cholesterol homeostasis prior to MBCD exposure prevented the extrusion of trophozoites. These results reveal importance of cholesterol during the intra-erythrocytic development of P. falciparum and the dramatic consequences resulting from tampering with cholesterol content in the infected erythrocyte. These findings suggest dynamic nature of cholesterol within the infected erythrocyte that is critical for parasite survival.

Regional differences in lipid composition and incorporation of saturated and unsaturated fatty acids into microsomal membranes of rat small intestine

1988 ◽  
Vol 66 (6) ◽  
pp. 794-800 ◽  
Author(s):  
M. L. Garg ◽  
M. Keelan ◽  
A. Wierzbicki ◽  
A. B. R. Thomson ◽  
M. T. Clandinin
Keyword(s):  
Fatty Acids ◽  
Small Intestine ◽  
Lipid Composition ◽  
Unsaturated Fatty Acids ◽  
Lipid Synthesis ◽  
Proximal Jejunum ◽  
Rat Small Intestine ◽  
Membrane Phospholipids ◽  
Significant Difference ◽  
Microsomal Membranes

Incorporation of [1-14C]palmitic (16:0) and [1-14C]linoleic (18:2ω6) acids into microsomal membranes of proximal (jejunum) and distal (ileum) regions of rat small intestine was investigated, and the lipid composition, including fatty acid profiles of membrane phospholipids, was determined. Jejunal microsomes contained significantly higher amounts of total phospholipids, phosphatidylcholine, and phosphatidylinositol, and lower amounts of cholesterol and sphingomyelin when compared with ileal microsomes. Jejunal microsomal phospholipids contained higher levels of stearic (18:0), 18:2ω6, and eicosapentaenoic (20:5ω3) acids followed by reduced levels of oleic (18:1ω9), arachidonic (20:4ω6), and docosahexaenoic (22:6ω3) acids when compared with those from the ileum, except for phosphatidylinositol where no significant difference between 20:4ω6 content of each site was observed. In both jejunal and ileal microsomes, incorporation of [1-14C]18:2ω6 was significantly higher than that of [1-14C]16:0. Incorporation of both [1-14C]16:0 and [1-14C]18:2ω6 was significantly higher in jejunal microsomal lipid fractions (phospholipids, diacylglycerols, triacylglycerols) when compared with the ileal microsomal fraction. These data suggest that (1) jejunal and ileal microsomal membranes differ from each other in terms of lipid composition and lipid synthesis, (2) site variations in the specificity of acyltransferases for different fatty acids exist, and (3) higher Δ9-, Δ6-, Δ5-, and Δ4-desaturase activities exist in ileal compared with jejunal enterocytes.

Isolation and Properties of a Novel Phospholipase a from Rat Brain That Hydrolyses Fatty Acids at sn-1 and sn-2 Positions

1998 ◽  
Vol 35 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Yosuke Tsujishita ◽  
Françoise Hullin ◽  
Kimihisa Yoshida ◽  
Shun-Ichi Nakamura ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Phosphatidic Acid ◽  
Molecular Mass ◽  
Rat Brain ◽  
Column Chromatography ◽  
Soluble Fraction ◽  
Gel Filtration ◽  
Phospholipase A ◽  
Membrane Phospholipids ◽  
Arachidonic Acids

A Ca2+-independent phospholipase A that releases various fatty acids from sn-1 and sn-2 positions was partially purified from rat brain soluble fraction. The enzyme showed an approximate molecular mass of 300 kDa on gel filtration column chromatography. Its enzymatic properties are distinct from those of well characterized phospholipase A2 enzymes; by using a series of synthetic phosphatidylcholines, the enzyme cleaved oleic, linoleic, and arachidonic acids like phospholipase A2, and released palmitic and stearic acids like phospholipase A1. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid were hydrolysed with almost equal efficiencies by this enzyme. These results indicate that the enzyme isolated is a novel Ca2+ -independent intracellular phospholipase A that might be responsible for production of various fatty acids from membrane phospholipids.

scholarly journals Hexadecenoic Fatty Acid Positional Isomers and de Novo PUFA Synthesis in Colon Cancer Cells

2019 ◽  
Author(s):  
Roberta Scanferlato ◽  
Massimo Bortolotti ◽  
Anna Sansone ◽  
Chryssostomos Chatgilialoglu ◽  
Letizia Polito ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cancer Cells ◽  
Palmitoleic Acid ◽  
De Novo ◽  
Fluorescent Microscopy ◽  
Positional Isomers ◽  
Membrane Phospholipids ◽  
Two Photon ◽  
Palmitic Acids

Palmitic acid metabolism involves delta-9 and delta-6 desaturase enzymes forming palmitoleic acid (9cis-16:1; n-7 series) and sapienic acid (6cis-16:1; n-10 series), respectively. The corresponding biological consequences and lipidomic research on these positional MUFA isomers are under development. Furthermore, sapienic acid can bring to the de novo synthesis of the n-10 polyunsaturated fatty acid (PUFA) sebaleic acid (5cis,8cis-18:2), but such transformations in cancer cells are not known. The model of Caco-2 cell line was used to monitor sapienic acid supplementation (150 and 300 μM) and evidence the formation of n-10 fatty acids as well as their incorporation at levels of membrane phospholipids and triglycerides. Comparison with palmitoleic and palmitic acids evidenced that lipid remodeling was influenced by the type of fatty acid and positional isomer, with increase of 8cis-18:1, n-10 PUFA and decrease of saturated fats in case of sapienic acid. Cholesteryl esters were formed only in case of sapienic acid. EC50 of sapienic acid (232.3 μM at 96 hrs) was the highest found among the tested fatty acids, thus influencing cell viability that was only reduced at 25% at 300 μM, whereas palmitoleic acid induced cell death. Two-photon fluorescent microscopy with Laurdan as a fluorescent dye provided information on membrane fluidity, highlighting that sapienic acid increases the distribution of fluid regions, probably connected with the formation of 8cis-18:1 and the n-10 PUFA in cell lipidome. Our results bring evidence for MUFA positional isomers and de novo PUFA synthesis for developing lipidomic analysis and cancer research.

scholarly journals Very long-chain acyl-CoA synthetase 3 mediates onco-sphingolipid metabolism in malignant glioma

2021 ◽  
Vol 9 (5) ◽  
Author(s):  
Elizabeth Kolar ◽  
Xiaohai Shi ◽  
Emily Clay ◽  
Ann Moser ◽  
Bachchu Lal ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cell Line ◽  
De Novo ◽  
Malignant Gliomas ◽  
Sphingolipid Metabolism ◽  
Membrane Microdomains ◽  
Membrane Phospholipids ◽  
Chain Acyl ◽  
Long Chain

Gliomas are the largest category of primary malignant brain tumors in adults, and glioblastomas account for nearly half of malignant gliomas. Glioblastomas are notoriously aggressive and drug-resistant, with a very poor 5 year survival rate of about 5%. New approaches to treatment are thus urgently needed. We previously identified an enzyme of fatty acid metabolism, very long-chain acyl-CoA synthetase 3 (ACSVL3), as a potential therapeutic target in glioblastoma. Using the glioblastoma cell line U87MG, we created a cell line with genomic deletion of ACSVL3 (U87-KO) and investigated potential mechanisms to explain how this enzyme supports the malignant properties of glioblastoma cells. Compared to U87MG cells, U87-KO cells grew slower and assumed a more normal morphology. They produced fewer, and far smaller, subcutaneous xenografts in nude mice. Acyl-CoA synthetases, including ACSVL3, convert fatty acids to their acyl-CoA derivatives, allowing participation in diverse downstream lipid pathways. We examined the effect of ACSVL3 depletion on several such pathways. Fatty acid degradation for energy production was not affected in U87-KO cells. Fatty acid synthesis, and incorporation of de novo synthesized fatty acids into membrane phospholipids needed for rapid tumor cell growth, was not significantly affected by lack of ACSVL3. In contrast, U87-KO cells exhibited evidence of altered sphingolipid metabolism. Levels of ceramides containing 18-22 carbon fatty acids were significantly lower in U87-KO cells. This paralleled the fatty acid substrate specificity profile of ACSVL3. The rate of incorporation of stearate, an 18-carbon saturated fatty acid, into ceramides was reduced in U87-KO cells, and proteomics revealed lower abundance of ceramide synthesis pathway enzymes. Sphingolipids, including gangliosides, are functional constituents of lipid rafts, membrane microdomains thought to be organizing centers for receptor-mediated signaling. Both raft morphology and ganglioside composition were altered by deficiency of ACSVL3. Finally, levels of sphingosine-1-phosphate, a sphingolipid signaling molecule, were reduced in U87-KO cells. We conclude that ACSVL3 supports the malignant behavior of U87MG cells, at least in part, by altering cellular sphingolipid metabolism.

scholarly journals An Insight into Storage Lipid Synthesis by Yarrowia lipolytica Yeast Relating to Lipid and Sugar Substrates Metabolism

Biomolecules ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 685 ◽  
Author(s):  
Fabiszewska ◽  
Misiukiewicz-Stępień ◽  
Paplińska-Goryca ◽  
Zieniuk ◽  
Białecka-Florjańczyk
Keyword(s):  
Fatty Acids ◽  
Olive Oil ◽  
De Novo ◽  
Lipid Synthesis ◽  
Carbon Substrate ◽  
Atp Citrate Lyase ◽  
Oil Accumulation ◽  
Storage Lipids ◽  
Real Time Quantitative Pcr ◽  
Key Enzyme

Single cell oil (SCO) is the lipid accumulated in the cells of oleaginous microorganisms. Cellular lipids can be synthesized in two different pathways: de novo by metabolizing hydrophilic substrates and ex novo by fermenting hydrophobic substrates. The aim of the study was to evaluate the effect of carbon source (glucose and olive oil) in the culture medium on the course of microbial oil accumulation in Y. lipolytica cells. The level of selected gene expression by real time quantitative PCR method was investigated. The significant increase in expression of the POX2 gene encoding acyl-CoA oxidase II, which preferentially oxidizes long-chain acyl-CoAs formed from substrate fatty acids incorporated inside the microbial cell, was observed in medium with olive oil in relation to glucose containing medium. Noteworthily, the presence of lipid carbon substrate did not inhibit the level of ACL gene transcription coding for ATP-citrate lyase, the key enzyme of the lipid de novo accumulation process. The present study indicated that de novo lipid biosynthesis could occur despite the presence of fatty acids in the medium, and the synthesis of storage lipids in the presence of lipid carbon substrates could be carried out with the use of both pathways (de novo and ex novo).

Sign in / Sign up

Export Citation Format

Share Document