Abnormal glutathione transport in cystic fibrosis airway epithelia.
Glutathione (GSH) is a potentially important component of antioxidant defense in the epithelial lung lining fluid. Cystic fibrosis (CF) patients have chronic inflammation in which oxidative stress can be a factor. To examine the hypothesis that the transport of GSH content was defective in CF patients, intracellular and extracellular GSH were measured by HPLC. Four cell lines were used: CFT1 cells [with defective CF transmembrane conductance regulator (CFTR), DeltaF508 homozygous, two clones] and one of the CFT1 clones transfected with either normal CFTR (CFTR repleted) or beta-galactosidase. GSH content in the apical fluid was 55% lower in CFTR-deficient cultures than in CFTR-repleted cells (P < 0.001). In contrast, intracellular GSH content was similar in CFT1 cells and CFTR-repleted cells. gamma-Glutamyl transpeptidase activity, which degrades extracellular GSH, did not account for differences in apical GSH. Rather, GSH efflux of CFTR-deficient cells was lower than that of CFTR-repleted cells. These studies suggested that decreased GSH content in the apical fluid in CF resulted from abnormal GSH transport associated with a defective CFTR.
Department of Molecular Pharmacology and Toxicology, Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, California 90033, USA.
L
L
Gao
K J
KJ
Kim
J R
JR
Yankaskas
H J
HJ
Forman
D001692:Biological Transport / Q000502:physiology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003550:Cystic Fibrosis / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000172:deficiency; D004847:Epithelial Cells / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D014132:Trachea / Q000378:metabolism* / Q000473:pathology; D005723:gamma-Glutamyltransferase / Q000378:metabolism
C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005723:gamma-Glutamyltransferase; D005978:Glutathione