Abnormal gangliosides are localized in lipid rafts in Sanfilippo (MPS3a) mouse brain

G. Dawson, M. Fuller, K. M. Helmsley, J. J. Hopwood

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Allogenic stem cell transplantation can reduce lysosomal storage of heparan sulfate-derived oligosaccharides by up to 27 % in Sanfilippo MPS3a brain, but does not reduce the abnormal storage of sialolactosylceramide (GM3) or improve neurological symptoms, suggesting that ganglioside storage is in a non-lysosomal compartment. To investigate this further we isolated the Triton X100-insoluble at 4 °C, lipid raft (LR) fraction from a sucrosedensity gradient from cerebral hemispheres of a 7 month old mouse model of Sanfilippo MPS3a and age-matched control mouse brain. HPLC/MS/MS analysis revealed the expected enrichment of normal complex gangliosides, ceramides, galatosylceramides and sphingomyelin enrichment in this LR fraction. The abnormal HS-derived oligosaccharide storage material was in the Triton X100-soluble at 4 °C fractions (8-12), whereas both GM3 and sialo[GalNAc]lactosylceramide (GM2) were found exclusively in the LR fraction (fractions 3 and 4) and were >90 % C18:0 fatty acid, suggesting a neuronal origin. Further analysis also revealed a >threefold increase in the late-endosome marker bis (monoacylglycerol) phosphate (>70 % as C22:6/22:6-BMP) in non-LR fractions 8-12 whereas different forms of the proposed BMP precursor, phosphatidylglycerol (PG) were in both LR and non-LR fractions and were less elevated in MPS3a brain. Thus heparan sulfate-derived oligosaccharide storage is associated with abnormal lipid accumulation in both lysosomal (BMP) and non-lysosomal (GM3 and GM2) compartments.

Original languageEnglish
Pages (from-to)1372-1380
Number of pages9
JournalNeurochemical Research
Volume37
Issue number6
DOIs
Publication statusPublished - 1 Jun 2012
Externally publishedYes

Keywords

  • Bis(monoacylglycerol) phosphate
  • Gangliosides
  • Lipid rafts
  • Mass-spectrometry
  • Mouse brain
  • Sanfilippo

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