Glial cells as a model for the role of cobalamin in the nervous system

Impaired synthesis of cobalamin coenzymes in cultured human astrocytes following short-term cobalamin-deprivation

Ewa H. Pezacka, Donald W. Jacobsen, Kathy Luce, Ralph Green

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The conversion of cyanocobalamin to adenosyl- and methylcobalamin is impaired in cobalamin-deficient cultured human glial cells. In contrast cultured human skin fibroblasts retained their ability to synthesize coenzyme forms when grown in cobalamin-deficient medium. Cells were pre-conditioned by growing in cobalamin-deficient media for six weeks and then subcultured in medium containing either free or transcobalamin II-bound 57Co-cyanocobalamin. Although both coenzyme levels were low in cobalamin-deficient glial cells, the decrease in methylcobalamin was more marked than that of adenosylcobalamin. Methionine synthase and Cbl reductase activities were markedly decreased in cobalamin-deficient glial cells but were unchanged in fibroblasts cultured in cobalamin-deficient medium. Our data suggest that in glial cells, cobalamin coenzyme synthesis and function is exquisitely sensitive to short-term cobalamin deprivation. Glial cells apparently synthesize and secrete transcobalamin II since antibodies directed against the transport protein inhibit the uptake of free cobalamin.

Original languageEnglish (US)
Pages (from-to)832-839
Number of pages8
JournalBiochemical and Biophysical Research Communications
Volume184
Issue number2
DOIs
StatePublished - Apr 30 1992
Externally publishedYes

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Coenzymes
Neurology
Vitamin B 12
Neuroglia
Astrocytes
Nervous System
Transcobalamins
Fibroblasts
5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase
Skin
Carrier Proteins
Oxidoreductases

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

Cite this

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title = "Glial cells as a model for the role of cobalamin in the nervous system: Impaired synthesis of cobalamin coenzymes in cultured human astrocytes following short-term cobalamin-deprivation",
abstract = "The conversion of cyanocobalamin to adenosyl- and methylcobalamin is impaired in cobalamin-deficient cultured human glial cells. In contrast cultured human skin fibroblasts retained their ability to synthesize coenzyme forms when grown in cobalamin-deficient medium. Cells were pre-conditioned by growing in cobalamin-deficient media for six weeks and then subcultured in medium containing either free or transcobalamin II-bound 57Co-cyanocobalamin. Although both coenzyme levels were low in cobalamin-deficient glial cells, the decrease in methylcobalamin was more marked than that of adenosylcobalamin. Methionine synthase and Cbl reductase activities were markedly decreased in cobalamin-deficient glial cells but were unchanged in fibroblasts cultured in cobalamin-deficient medium. Our data suggest that in glial cells, cobalamin coenzyme synthesis and function is exquisitely sensitive to short-term cobalamin deprivation. Glial cells apparently synthesize and secrete transcobalamin II since antibodies directed against the transport protein inhibit the uptake of free cobalamin.",
author = "Pezacka, {Ewa H.} and Jacobsen, {Donald W.} and Kathy Luce and Ralph Green",
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T2 - Impaired synthesis of cobalamin coenzymes in cultured human astrocytes following short-term cobalamin-deprivation

AU - Pezacka, Ewa H.

AU - Jacobsen, Donald W.

AU - Luce, Kathy

AU - Green, Ralph

PY - 1992/4/30

Y1 - 1992/4/30

N2 - The conversion of cyanocobalamin to adenosyl- and methylcobalamin is impaired in cobalamin-deficient cultured human glial cells. In contrast cultured human skin fibroblasts retained their ability to synthesize coenzyme forms when grown in cobalamin-deficient medium. Cells were pre-conditioned by growing in cobalamin-deficient media for six weeks and then subcultured in medium containing either free or transcobalamin II-bound 57Co-cyanocobalamin. Although both coenzyme levels were low in cobalamin-deficient glial cells, the decrease in methylcobalamin was more marked than that of adenosylcobalamin. Methionine synthase and Cbl reductase activities were markedly decreased in cobalamin-deficient glial cells but were unchanged in fibroblasts cultured in cobalamin-deficient medium. Our data suggest that in glial cells, cobalamin coenzyme synthesis and function is exquisitely sensitive to short-term cobalamin deprivation. Glial cells apparently synthesize and secrete transcobalamin II since antibodies directed against the transport protein inhibit the uptake of free cobalamin.

AB - The conversion of cyanocobalamin to adenosyl- and methylcobalamin is impaired in cobalamin-deficient cultured human glial cells. In contrast cultured human skin fibroblasts retained their ability to synthesize coenzyme forms when grown in cobalamin-deficient medium. Cells were pre-conditioned by growing in cobalamin-deficient media for six weeks and then subcultured in medium containing either free or transcobalamin II-bound 57Co-cyanocobalamin. Although both coenzyme levels were low in cobalamin-deficient glial cells, the decrease in methylcobalamin was more marked than that of adenosylcobalamin. Methionine synthase and Cbl reductase activities were markedly decreased in cobalamin-deficient glial cells but were unchanged in fibroblasts cultured in cobalamin-deficient medium. Our data suggest that in glial cells, cobalamin coenzyme synthesis and function is exquisitely sensitive to short-term cobalamin deprivation. Glial cells apparently synthesize and secrete transcobalamin II since antibodies directed against the transport protein inhibit the uptake of free cobalamin.

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