Arterial dermatan sulfate proteoglycan structure in pigeons susceptible to atherosclerosis

Arterial dermatan sulfate proteoglycans (DS-PG) were isolated from randomly bred White Carneau (RBWC) pigeons and a line of White Carneau pigeons (WC-2) genetically selected for increased atherosclerosis susceptibility. To characterize the basic proteoglycan (PG) structure and to identify structural differences that may relate to a specific arterial phenotype, embryos were labeled with radioactive sulfate in ovo and PG were isolated from aortas with 4.0 M GdnHCl. DS-PG were separated from chondroitin sulfate PG by gel chromatography and further purified by CsCl buoyant density ultracentrifugation and ion-exchange of chromatography. The DS-PG monomers from the two genetic lines of pigeons eluted at different positions on two high pressure liquid chromatography (HPLC) gel permeation systems, which suggested a structural difference between the two monomers. Analysis of the monomer components showed a similar protein core molecular weight of 50,000 for each and a similar amino acid composition. Glycosaminoglycans (GAG) molecular weights were estimated to be 15,000 for WC-2 and 18,000 for RBWC. The findings suggest a basic difference in post-translational processing of PG in the two pigeon types which may reflect distinct functional properties associated with resistance or susceptibility to atherosclerosis.