The degradative pathway of gangliosides GM1 and GM2 in Neuro2a cells by sialidase

L. Riboni, A. Caminiti, R. Bassi, G. Tettamanti

Research output: Contribution to journalArticle

Abstract

Gangliosides GM1 [3H-labeled at the sphingosine (Sph) moiety] and GM2 [3H-labeled at the Sph or N-acetylgalactosamine (GalNAc) moiety] were administered to cultured Neuro2a cells for varying pulse (1-4 h) and chase (up to 4 h) periods, and their metabolic processing was followed. The main and earliest formed 3H-metabolites of [Sph-3H]GM1 were GM2, asialo-GM1, asialo-GM2, and lactose-ceramide, and those of [Sph-3H)GM2 were asialo- GM2 and lactose-ceramide. The asialo-GM1 and asialo-GM2 formed were isolated and chemically characterized, [3H]Asialo-GM2 was produced in identical amounts after treatment with equimolar [Sph-3H]GM2 and [GalNAc- 3H]GM2. At low temperature or in the presence of chloroquine, the formation of all 3H-metabolites, including asialo-GM2 and asialo-GM1, was undetectable, indicating that ganglioside metabolic processing was an endocytosis- and lysosome-dependent process. These results demonstrate that in Neuro2a cells exogenous GM1 (and GM2) is mainly degraded through the pathway GM1 → GM2 → asialo-GM2 →→ Sph, with a minor fraction of GM1 undergoing degradation with the sequence GM1 → asialo-GM1 → asialo- GM2 →→ Sph. These findings are consistent with the hypothesis that Neuro2a cells contain a sialidase (likely of lysosomal nature) affecting ganglioside GM1 and GM2. The sialidase-mediated degradative pathway of GM1 and GM2 in Neuro2a cells might be related to the tumoral nature of these cells.

Original languageEnglish
Pages (from-to)451-454
Number of pages4
JournalJournal of Neurochemistry
Volume64
Issue number1
Publication statusPublished - 1995

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Keywords

  • Cell culture
  • Ganglioside metabolism
  • Neuroblastoma cells
  • Sialidase

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

Riboni, L., Caminiti, A., Bassi, R., & Tettamanti, G. (1995). The degradative pathway of gangliosides GM1 and GM2 in Neuro2a cells by sialidase. Journal of Neurochemistry, 64(1), 451-454.