Sulfation of chondroitin/dermatan sulfate by cystic fibrosis pancreatic duct cells is not different from control cells.
Cystic fibrosis is associated with mutations of the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-regulated plasma membrane chloride channel. Cystic fibrosis patients have been reported to possess elevated sulfation of glycoconjugates, which may contribute to the pathogenesis of the disease. Sulfation of glycosaminoglycans by a cystic fibrosis pancreatic adenocarcinoma cell line homozygous for DeltaF508 (CFPAC-1), a control pancreatic cell line (PANC-1), two CFPAC-1 cell lines transfected with the gene for CFTR (PLJ-CFTR-4.7, TR20), and a mock-transfected CFPAC-1 control (PLJ-6) was investigated. Cells were radiolabeled with [35S]sulfate and [3H]glucosamine, and glycosaminoglycans secreted into the medium after 24 and 72 h were isolated. Chondroitinase ABC digestion of chondroitin/dermatan sulfate allowed the recovery of disaccharides which were analyzed for their degree of sulfation by strong anion-exchange HPLC. No differences in the extent of sulfation by any of the cell lines were noted. However, glycoaminoglycans synthesized by cystic fibrosis cells consistently exhibited twofold higher [35S]-sulfate:[3H]glucosamine ratios than the controls. We conclude that CFTR plays no role in the sulfation of chondroitin/dermatan sulfate by pancreatic cells and that isotope incorporation ratios alone are insufficient evidence of changes in sulfation levels.
Hill
W G
WG
Department of Chemical Pathology, Women's and Children's Hospital, Adelaide, South Australia, 5006. whill+@pitt.edu
Harper
G S
GS
Rozaklis
T
T
Hopwood
J J
JJ
D002460:Cell Line; D002809:Chondroitin Sulfates / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000502:physiology; D003871:Dermatan Sulfate / Q000378:metabolism*; D006801:Humans; D010183:Pancreatic Ducts / Q000378:metabolism*
C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003871:Dermatan Sulfate; D002809:Chondroitin Sulfates