Synthesis of choline phospholipids in neuronal and glial cell cultures by the methylation pathway

Dainous, Francine; Freysz, L.; Mozzi, Rita; Dreyfus, H.; Louis, Jean‐Claude; Porcellati, G; Massarelli, R.

doi:10.1016/0014-5793(82)80740-0

Cited by 33 publications

(9 citation statements)

References 14 publications

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“…1, reaction 13), a process that has been demonstrated to occur in rat brain and neuronal cultures (Andriamampandry et al, 1989(Andriamampandry et al, , 1990. However, this methylation activity is higher in neuronal than in glial cells (Dainous et al, 1982). Incorporation of ['4CI EA via this path would fit with the label kinetics of PB and PC (Fig.…”

Section: Methylation Of Ea Moieties Contributes But a Minor Fraction mentioning

confidence: 82%

“…One should keep in mind that brain is a very heterogeneous tissue and that possibly some of the cells in the CNS, i.e., oligodendrocytes, might be relatively enriched in PEMT activity. Indeed, it has been shown (Dainous et al, 1982) that the PE methylation activity is much higher in glial cells than in neurons and that PBMT activity is intrinsic to myelin (Tsvetnitsky et al, 1995). Choline reuptake by neurons after neurotransmission is highly efficient, and thus the amounts of extracellular choline available for oligodendrocytes might be limited.…”

Section: Methylation Of Ea Moieties Contributes But a Minor Fraction mentioning

confidence: 99%

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Relationships Between Phosphatidylcholine, Phosphatidylethanolamine, and Sphingomyelin Metabolism in Cultured Oligodendrocytes

Vos

Haas

Golde

et al. 1997

Journal of Neurochemistry

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Abstract:In most cell types the major pathway of sphingomyelin synthesis is the direct transfer of the phosphocholine head group from phosphatidylcholine to ceramide catalyzed by the enzyme L-acylsphingosine:phosphatidylcholine phosphocholinetransferase (SM synthase; EC 2.7.8.-). Although this pathway has been demonstrated in brain tissue, its quantitative importance has been questioned. An alternative biosynthetic pathway for sphingomyelin synthesis in brain tissue has been proposed, viz., the direct transfer of phosphoethanolamine from phosphatidylethanolamine to ceramide, followed by methylation of the ethanolamine moiety to a choline group. We have evaluated various possible biosynthetic pathways of sphingomyelin synthesis in rat spinal cord oligodendrocytes, the myelin-forming cells of the CNS, by labeling cells in culture with radiolabeled choline, ethanolamine, or serine. Our results indicate that, in oligodendrocytes, most of the phosphocholine for the biosynthesis of sphingomyelin is provided by phosphatidylcholine, which is predominantly derived from de novo synthesis. No evidence was found for the operation of the alternative pathway via ceramide-phosphoethanolamine. Furthermore, our results indicate that a small pool of phosphatidylcholine is provided by methylation of phosphatidylethanolamine, which in turn is formed preferentially by decarboxylation of phosphatidylserine.

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Section: Methylation Of Ea Moieties Contributes But a Minor Fraction mentioning

confidence: 82%

Section: Methylation Of Ea Moieties Contributes But a Minor Fraction mentioning

confidence: 99%

Relationships Between Phosphatidylcholine, Phosphatidylethanolamine, and Sphingomyelin Metabolism in Cultured Oligodendrocytes

Vos

Haas

Golde

et al. 1997

Journal of Neurochemistry

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“…Studies from several laboratories have documented the existence of the appropriate enzymes and the capability of brain tissue to convert EPG to CPG (Chida and Arakawa, 1971;Blusztajn et al, 1979;Crews et al, 1980). Nerve cell cultures also convert labeled ethanolamine into CPG (Dainous et al, 1982).…”

Section: Discussionmentioning

confidence: 99%

“…Stepwise methylation has been studied in C6 astrocytoma (Strittmater et a]., 1979), rat cerebral neurons , PC12 pheochromocytoma (Maeda et al, 1981), and chick embryo primary cultures (Dainous et a]., 1982). In spite of this, data concerning the contribution of this pathway to the overall synthesis of CPG in the nervous tissue and its metabolic requirement in intact cells still are very limited.…”

mentioning

confidence: 99%

Polar Head Group Decarboxylation and Methylation of Phospholipids: An Alternate Route for Phosphatidylcholine Formation in Cultured Neuronal Cells

Yavin

1985

Journal of Neurochemistry

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Decarboxylation of phosphatidylserine (SPG) and methionine-dependent, stepwise methylation of phosphatidylethanolamine (EPG) to form phosphatidylcholine (CPG) were examined in monolayer cultures of rat cerebral cells. Ethanolamine, monomethylaminoethanol, or dimethylaminoethanol nitrogenous bases (N-bases) added to culture medium at millimolar level result each in synthesis of the corresponding phospholipid via a de novo pathway at initial rates of 0.18, 0.30, and 0.36 nmol/h/micrograms DNA, respectively. Addition of methyl-labeled methionine to culture medium at tracer levels or at millimolar concentration enabled measurements of the rates of phospholipid methylation from EPG phosphatidylmonomethylaminoethanol (Me1EPG) and phosphatidyldimethylaminoethanol (Me2EPG) precursors. At tracer doses, the rates of methylation from the above respective phospholipids are 0.45, 1.17, and 1.70 pmol/h/micrograms DNA. At 1 mM methionine, synthesis of CPG proceeds from [14C]EPG or [14C]Me2EPG at initial rates of 8 and 17 pmol/h/micrograms DNA, respectively. Although the latter phospholipid analog can be generated from its monomethyl precursor, methylation of EPG does not result in the accumulation of Me2EPG, suggesting two segregated and metabolically distinct pathways. In the presence of N-bases, of the total [3H]serine incorporated into cellular phospholipids 30-36.5% of labelled SPG is converted into decarboxylation products. The decarboxylation and methylation routes contribute a significant portion of choline from endogenous sources, most likely through conversion of SPG.

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“…There is a generalized increase in lipid-synthesizing activity during the second week of life in the rat brain, specifically choline incorporation into PtdCho by the CDP-choline pathway (Abdel-Latif & Smith, 1972), elongation of fatty acids (Aeberhard et al, 1969), cholesterol synthesis (Jones et al, 1975) and sulphate incorporation into sulphatides (McKhann & Ho, 1967) are all highest during that period. Myelin synthesis is also maximal during this time (Welles & Dittmer, 1967); indeed it has been shown that cultured chick glia have higher activity of PeMT than cultured chick neurons (Dainous et al, 1982).…”

Section: Conversion Of Ptdme2etn To Ptdchomentioning

confidence: 95%

Developmental changes in the activity of phosphatidylethanolamine N-methyltransferases in rat brain

Blusztajn¹,

Zeisel²,

Wurtman³

1985

Biochemical Journal

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The activity of phosphatidylethanolamine N-methyltransferase (PeMT), an enzymic system that catalyses the synthesis of phosphatidylcholine (PtdCho) via sequential methylation of phosphatidylethanolamine (PtdEtn) using S-adenosylmethionine (AdoMet) as a methyl donor, was examined in brain homogenates from rats of various ages. The data thus obtained were consistent with the existence of two distinct enzyme activities within this enzyme system, i.e. one catalysing the methylation of PtdEtn [to form phosphatidyl-N-monomethylethanolamine (PtdMeEtn)], and the other catalysing the methylations of PtdMeEtn and phosphatidyl-NN-dimethylethanolamine (PtdMe2Etn) (to form PtdMe2Etn and PtdCho, respectively). PeMT (PtdEtn-methylating) activity per g of brain was 4-fold higher in neonatal than in adult brains. The enzyme activity in adult brains exhibited Michaelis-Menten kinetics for AdoMet, and its affinity for AdoMet was high (apparent Km 1.6 microM). In neonatal brain the relationships between AdoMet concentrations and PtdMeEtn formation were more complex: a sigmoidal component (with a Hill coefficient of 2.7), requiring 90 microM-AdoMet for half-saturation predominated over the high-affinity component (similar to that of the adult brain). PeMT (PtdMe2Etn-methylating) activity per g of brain increased 2-fold between the 5th and the 20th postnatal days and remained constant thereafter; it was higher than that of PeMT (PtdEtn-methylating) activity at all ages studied, and its affinity for AdoMet was low (apparent Km 99 microM). No sexual dimorphism in brain PeMT activity was observed at any age. We conclude that PeMT (PtdEtn-methylating) catalyses the rate-limiting step in PtdCho synthesis in rat brain, and that PtdCho formation via this pathway may be greatest during the neonatal period.

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Synthesis of choline phospholipids in neuronal and glial cell cultures by the methylation pathway

Cited by 33 publications

References 14 publications

Relationships Between Phosphatidylcholine, Phosphatidylethanolamine, and Sphingomyelin Metabolism in Cultured Oligodendrocytes

Relationships Between Phosphatidylcholine, Phosphatidylethanolamine, and Sphingomyelin Metabolism in Cultured Oligodendrocytes

Polar Head Group Decarboxylation and Methylation of Phospholipids: An Alternate Route for Phosphatidylcholine Formation in Cultured Neuronal Cells

Developmental changes in the activity of phosphatidylethanolamine N-methyltransferases in rat brain

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