Dataset Information

Legionella dumoffii utilizes exogenous choline for phosphatidylcholine synthesis.

ABSTRACT: Phosphatidycholine (PC) is the major membrane-forming phospholipid in eukaryotes but it has been found in only a limited number of prokaryotes. Bacteria synthesize PC via the phospholipid N-methylation pathway (Pmt) or via the phosphatidylcholine synthase pathway (Pcs) or both. Here, we demonstrated that Legionella dumoffii has the ability to utilize exogenous choline for phosphatidylcholine (PC) synthesis when bacteria grow in the presence of choline. The Pcs seems to be a primary pathway for synthesis of this phospholipid in L. dumoffii. Structurally different PC species were distributed in the outer and inner membranes. As shown by the LC/ESI-MS analyses, PC15:0/15:0, PC16:0/15:0, and PC17:0/17:1 were identified in the outer membrane and PC14:0/16:0, PC16:0/17:1, and PC20:0/15:0 in the inner membrane. L. dumoffii pcsA gene encoding phosphatidylcholine synthase revealed the highest sequence identity to pcsA of L. bozemanae (82%) and L. longbeachae (81%) and lower identity to pcsA of L. drancourtii (78%) and L. pneumophila (71%). The level of TNF-? in THP1-differentiated cells induced by live and temperature-killed L. dumoffii cultured on a medium supplemented with choline was assessed. Live L. dumoffii bacteria cultured on the choline-supplemented medium induced TNF-? three-fold less efficiently than cells grown on the non-supplemented medium. There is an evident effect of PC modification, which impairs the macrophage inflammatory response.

SUBMITTER: Palusinska-Szysz M

PROVIDER: S-EPMC4057730 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Legionella dumoffii utilizes exogenous choline for phosphatidylcholine synthesis.

Palusinska-Szysz Marta M Szuster-Ciesielska Agnieszka A Kania Magdalena M Janczarek Monika M Chmiel Elżbieta E Danikiewicz Witold W

International journal of molecular sciences 20140509 5

Phosphatidycholine (PC) is the major membrane-forming phospholipid in eukaryotes but it has been found in only a limited number of prokaryotes. Bacteria synthesize PC via the phospholipid N-methylation pathway (Pmt) or via the phosphatidylcholine synthase pathway (Pcs) or both. Here, we demonstrated that Legionella dumoffii has the ability to utilize exogenous choline for phosphatidylcholine (PC) synthesis when bacteria grow in the presence of choline. The Pcs seems to be a primary pathway for s ...[more]

PMID: 24821544

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Project description:Although single nucleotide polymorphisms (SNPs) in folate-mediated pathways predict susceptibility to choline deficiency during severe choline deprivation, it is unknown if effects persist at recommended intakes. Thus, we used stable isotope liquid chromatography-mass spectrometry (LC-MS) methodology to examine the impact of candidate SNPs on choline metabolism in a long-term, randomized, controlled feeding trial among pregnant, lactating, and nonpregnant (NP) women consuming 480 or 930 mg/d choline (22% as choline-d9, with d9 indicating a deuterated trimethyl amine group) and meeting folate-intake recommendations. Variants impairing folate metabolism, methylenetetrahydrofolate reductase (MTHFR) rs1801133, methionine synthase (MTR) rs1805087 [wild-type (WT)], MTR reductase (MTRR) rs1801394, and methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase (MTHFD1) rs2236225, influenced choline dynamics, frequently through interactions with reproductive state and choline intake, with fewer genotypic alterations observed among pregnant women. Women with these variants partitioned more dietary choline toward phosphatidylcholine (PC) biosynthesis via the cytidine diphosphate (CDP)-choline pathway at the expense of betaine synthesis even when use of betaine as a methyl donor was increased. Choline intakes of 930 mg/d restored partitioning of dietary choline between betaine and CDP-PC among NP (MTHFR rs1801133 and MTR rs1805087 WT) and lactating (MTHFD1 rs2236225) women with risk genotypes. Overall, our findings indicate that loss-of-function variants in folate-metabolizing enzymes strain cellular PC production, possibly via impaired folate-dependent phosphatidylethanolamine-N-methyltransferase (PEMT)-PC synthesis, and suggest that women with these risk genotypes may benefit from choline intakes exceeding current recommendations.-Ganz, A. B., Shields, K., Fomin, V. G., Lopez, Y. S., Mohan, S., Lovesky, J., Chuang, J. C., Ganti, A., Carrier, B., Yan, J., Taeswuan, S., Cohen, V. V., Swersky, C. C., Stover, J. A., Vitiello, G. A., Malysheva, O. V., Mudrak, E., Caudill, M. A. Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis.

Project description:In mammals, oleic acid (OA) induces pulmonary edema (PE), which can initiate acute lung injury (ALI) and lead to acute respiratory distress syndrome (ARDS). Pulmonary surfactant (PS) plays a key role in a broad range of treatments for ARDS. The aim of the present investigation was to assess changes in the synthesis of phosphatidylcholine (PC) from choline and determine the effect of exogenous PS on its de novo synthesis in rats with OA-induced PE. Experimental rats were randomized into three groups, including a control group, OA-induced PE group, and OA-induced group treated with exogenous PS (OA-PS). Twenty-four rats were sacrificed 4 h after induction of the OA model, and tissue was examined by light and electron microscopy to assess the severity of ALI using an established scoring system at the end of the experiment. After 15 ?Ci 3H-choline chloride was injected intravenously, eight rats in each group were sacrificed at 4, 8, and 16 h. The radioactivity of 3H incorporated into total phospholipid (TPL) and desaturated phosphatidylcholine (DSPC) was measured in bronchoalveolar lavage fluid (BALF) and lung tissue (LT) using a liquid scintillation counter and was expressed as counts per minute (CPM). Results showed that TPL, DSPC, and the ratio of DSPC/total protein (TP) in lung tissue decreased 4 h after challenge with OA, but the levels recovered after 8 and 16 h. At 8 h after injection, 3H-TPL and 3H-DSPC radioactivity in the lungs reached its peak. Importantly, 3H-DSPC CPM were significantly lower in the PS treatment group (LT: Control: 62327 ± 9108; OA-PE: 97315 ± 10083; OA-PS: 45127 ± 10034, P < 0.05; BALF: Control: 7771 ± 1768; OA-PE: 8097 ± 1799; OA-PE: 3651 ± 1027, P < 0.05). Furthermore, DSPC secretory rate (SR) in the lungs was significantly lower in the PS treatment group at 4 h after injection (Control: 0.014 ± 0.003; OA-PE: 0.011 ± 0.004; OA-PS: 0.023 ± 0.006, P < 0.05). Therefore, we hypothesize that exogenous PS treatments may adversely affect endogenous de novo synthetic and secretory phospholipid pathways via feedback inhibition. This novel finding reveals the specific involvement of exogenous PS in endogenous synthetic and secretory phospholipid pathways during the treatment of ARDS. This information improves our understanding of how PS treatment is beneficial against ARDS and opens new opportunities for expanding its use.

Project description:BackgroundLipid metabolism in pregnancy delivers PUFAs from maternal liver to the developing fetus. The transition at birth to diets less enriched in PUFA is especially challenging for immature, extremely preterm infants who are typically supported by total parenteral nutrition.ObjectiveThe aim was to characterize phosphatidylcholine (PC) and choline metabolism in preterm infants and demonstrate the molecular specificity of PC synthesis by the immature preterm liver in vivo.MethodsThis MS-based lipidomic study quantified the postnatal adaptations to plasma PC molecular composition in 31 preterm infants <28 weeks' gestational age. Activities of the cytidine diphosphocholine (CDP-choline) and phosphatidylethanolamine-N-methyltransferase (PEMT) pathways for PC synthesis were assessed from incorporations of deuterated methyl-D9-choline chloride.ResultsThe concentration of plasma PC in these infants increased postnatally from median values of 481 (IQR: 387-798) µM at enrollment to 1046 (IQR: 616-1220) µM 5 d later (P < 0.001). Direct incorporation of methyl-D9-choline demonstrated that this transition was driven by an active CDP-choline pathway that synthesized PC enriched in species containing oleic and linoleic acids. A second infusion of methyl-D9-choline chloride at day 5 clearly indicated continued activity of this pathway. Oxidation of D9-choline through D9-betaine resulted in the transfer of 1 deuterated methyl group to S-adenosylmethionine. A very low subsequent transfer of this labeled methyl group to D3-PC indicated that liver PEMT activity was essentially inactive in these infants.ConclusionsThis study demonstrated that the preterm infant liver soon after birth, and by extension the fetal liver, was metabolically active in lipoprotein metabolism. The low PEMT activity, which is the only pathway for endogenous choline synthesis and is responsible for hormonally regulated export of PUFAs from adult liver, strongly supports increased supplementation of preterm parenteral nutrition with both choline and PUFAs.

Dataset Information

Legionella dumoffii utilizes exogenous choline for phosphatidylcholine synthesis.

Publications

Legionella dumoffii utilizes exogenous choline for phosphatidylcholine synthesis.

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