Journal of Molecular Neuroscience

, Volume 24, Issue 1, pp 167–172

Novel glycosaminoglycan precursors as antiamyloid agents

Part IV
  • Robert Kisilevsky
  • Walter A. Szarek
  • John Ancsin
  • Rahul Vohra
  • Zhanjiang Li
  • Sandra Marone
Anti-Amyloid

DOI: 10.1385/JMN:24:1:167

Cite this article as:
Kisilevsky, R., Szarek, W.A., Ancsin, J. et al. J Mol Neurosci (2004) 24: 167. doi:10.1385/JMN:24:1:167

Abstract

In vivo amyloids consist of two classes of constituents. The first is the disease-defining protein, β-amyloid (Aβ), in Alzheimer’s disease. The second is a set of common structural components that usually are the building blocks of basement membrane (BM), a tissue structure that serves as a scaffold onto which cells normally adhere. In vitro binding interactions between one of these BM components and amyloidogenic proteins rapidly change the conformation of the amyloidogenic protein into amyloid fibrils. The offending BM component is a heparan sulfate (HS) proteoglycan, part of which is protein and the remainder a specific linear polysaccharide, which is the portion responsible for binding and imparting the typical amyloid structure to the amyloid precursor protein/peptide. Our past work has demonstrated that agents that inhibit the binding between HS and the amyloid precursor are effective antiamyloid compounds both in vitro and in vivo. Similarly, 4-deoxy analogs of glucosamine (a precursor of HS biosynthesis) are effective antiamyloid compounds both in culture and in vivo. Our continuing work concerns (1) the testing of our 4-deoxy compounds in a mouse transgenic model of Alzheimer’s disease, and (2) the continuing design and synthesis of modified sugar precursors of HS, which when incorporated into the polysaccharide will alter its structure so that it affects its amyloid-inducing properties. Since our previous report, 22 additional compounds have been designed and synthesized based on the known steps involved in HS biosynthesis. Of these, 12 soluble compounds have been assessed for their effect on HS biosynthesis in hepatocyte tissue cultures. In addition, one anomer of a 4-deoxy-D-glucosamine analog, which possesses AA-amyloid inhibitory properties in vivo is in the process of being assessed for its anti-Aβ activity using a murine transgenic model of brain Aβ amyloidogenesis. The majority of the novel sugars prepared to date are analogs of N-acetylglucosamine. They have been modified at the 2-N, C-3, C-4, C-3 and C-4, or C-6 positions. One compound modified at the 2-N position (QS231), which inhibits HS synthesis in hepatocyte cultures, has shown marked enhancing properties vis-à-vis AA amyloid deposition in vivo. Very instructive results with regard to HS structure and its relation to AA amyloid deposition should be forthcoming from analyses of the AA-associated HS generated with this compound. Two additional compounds, QS431, modified at C-4, and QS610, modified at C-6, have been shown to have marked inhibitory and stimulatory effects, respectively, on hepatocyte HS synthesis. These compounds are presently being assessed in vivo in AA amyloid deposition models.

Index Entries

amyloidbindingglycosaminoglycans (GAGs)glucosamine analogsheparan sulfateSAA

Copyright information

© Humana Press Inc 2004

Authors and Affiliations

  • Robert Kisilevsky
    • 1
    • 3
  • Walter A. Szarek
    • 2
  • John Ancsin
    • 1
    • 3
  • Rahul Vohra
    • 2
  • Zhanjiang Li
    • 2
  • Sandra Marone
    • 2
  1. 1.Department of PathologyQeen’s UniversityCanada
  2. 2.Department of ChemistryQueen’s UniversityCanada
  3. 3.The Syl and Molly Apps Research Center Kingston Centeral HospitalKingstonCanada