Glycosaminoglycans of the porcine central nervous system

Abstract

Glycosaminoglycans (GAG) are known to participate in central nervous system processes such as development, cell migration, and neurite outgrowth. In this paper, we report an initial glycomics study on GAGs from porcine central nervous system. GAGs of the porcine central nervous system, brain and spinal cord, were isolated and purified by defating, proteolysis, anion-exchange chromatography and methanol precipitation. The isolated GAG content in brain was 5-times higher than in spinal cord (0.35 mg/g, compared to 0.07 mg/g dry sample). In both tissues, chondroitin sulfate (CS) and heparan sulfate (HS) were the major and the minor GAG. The average molecular weight of CS from brain and spinal cord was 35.5 and 47.1 kDa, respectively, and HS from brain and spinal cord was 56.9 and 34 kDa, respectively. The disaccharide analysis showed that the composition of CS from brain and spinal cords are similar with uronic acid (1→3) 4-O-sulfo-N-acetylgalactosamine residue corresponding to the major disaccharide unit (CS type-A) along with five minor disaccharide units. The major disaccharides of both brain and spinal cord HS were uronic acid (1→4) N-acetylglucosamine and uronic acid (1→4) 6-O-sulfo-N-sulfoglucosamine but their composition of minor disaccharides differed. Analysis by 1H- and two-dimensional-NMR spectroscopy confirmed these disaccharide analyses and provided the glucuronic/iduronic acid ratio. Finally, both purified CS and HS were biotinylated and immobilized on BIAcore SA biochips. Interactions between these GAGs and fibroblast growth factors (FGF1 and FGF2) and sonic hedgehog (Shh) were investigated by surface plasmon resonance.