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Cystic fibrosis (CF) is a fatal inherited disease caused by the loss of function of a plasma membrane chloride channel-the cystic fibrosis transmembrane conductance regulator (CFTR). It is characterized by viscous mucous secretions which have abnormal glycosylation and sulfation. The development of a CFTR knockout mouse has allowed in vivo experiments aimed at investigating the over-sulfation phenomenon reported for CF glycoconjugates. Four CF and five control mice injected with [35S]sulfate were examined for differences in the sulfation of glycosaminoglycans (GAGs) synthesized by 12 tissues after 48 h. The liver and pancreas of CF mice incorporated significantly higher amounts of [35S]sulfate into GAGs (dpm/microg) than the controls, while the ileum, jejunum, colon, cecum, spleen, trachea, and gall bladder of CF mice exhibited higher incorporation levels that were not significant. The lung and nasal septum were not different, and the nasal mucosa of CF mice was significantly lower (P0.05). Structural analysis of the chondroitin/dermatan sulfate component by strong anion-exchange HPLC revealed that the liver and ileum of CF mice incorporated significantly more total sulfate than controls. However, for other organs, the explanation for higher isotope incorporation was a 40-50% higher specific activity of [35S]sulfate within GAGs. This finding implied different uptake kinetics of sulfate from the circulation or that CF mice have altered sulfate pools. CF mice also had altered proportions of chondroitin/dermatan sulfate to heparan sulfate in the ileum and gall bladder (P0.05). We conclude that extracellular matrix architecture in some CF organs may be abnormal and that sulfation of glycoconjugates by some organs and sulfate utilization in others have been affected by the loss of CFTR. This study provides the first in vivo evidence for an influence of CFTR on glycoconjugate sulfation and suggests other secondary manifestations of CFTR dysfunction associated with abnormalities of the extracellular matrix.

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 ΔF 508 (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 [ 35 S]sulfate and [ 3 H]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 [ 35 S]-sulfate:[ 3 H]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.