Age-dependent reduction in sialidase activity of nuclear membranes from mouse brain

Megumi Saito, Hitoshi Hagita, Masaki Ito, Susumu Ando, Robert K Yu

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Sialidase is an enzyme that cleaves α-linked sialic acid residues from sialoglycoconjugates and participates in various cellular functions. In the present study, we characterized sialidase activity in nuclear membranes from mouse brain and examined its age-related changes. A highly purified nuclear membrane preparation from 4-week-old mouse brain contained sialidase activity that hydrolyzed both 4-methylumbelliferyl-α-D-N-acetylneuraminic acid (4MU-Neu5Ac) and ganglioside GM3. The specific activities directed toward both substrates were 6.33±0.77 and 13.4±1.1pmol/mgprotein/min, respectively. Nuclear localization of sialidase activity was confirmed by fluorescent cytochemistry of intact nuclei using 5-bromo-4-chloro-3-indolyl-α-D-N-acetylneuraminic acid (X-Neu5Ac) as the substrate. Age-related changes in nuclear sialidase activity in brain tissue were investigated using mice of different ages (i.e. 2-week-, 4-week-, 14-month-, and 26-month-old). Sialidase activity toward 4MU-Neu5Ac had almost identical levels at 2nd and 4th weeks, but thereafter decreased rapidly; the activity at 26 months was about one third of the young levels. Sialidase activity toward GM3 also showed a similar developmental pattern, though the reduction at advancing ages was less than that of activity toward 4MU-Neu5Ac. The present study demonstrates that the activity of nuclear sialidase decreases with aging. The reduced activity of nuclear sialidase may be implicated with alterations of neural cell function during aging.

Original languageEnglish (US)
Pages (from-to)937-941
Number of pages5
JournalExperimental Gerontology
Volume37
Issue number7
DOIs
StatePublished - Jul 2 2002

Keywords

  • 4-Methylumbelliferyl-N-acetylneuraminic acid
  • Brain
  • Fluorescent cytochemistry
  • GM3
  • Gangliosides
  • Mouse
  • Nuclear membrane
  • Sialidase
  • X-Neu5Ac

ASJC Scopus subject areas

  • Biochemistry
  • Aging
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Cell Biology

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