Cholesterol depletion and genistein as tools to promote F508delCFTR retention at the plasma membrane.
OBJECTIVE
F508delCFTR-, but not wtCFTR-, expressing fibroblasts resemble Niemann Pick type C cells in the massive intracellular accumulation of free cholesterol. The recruitment and activation of F508delCFTR by cholesterol depletion was studied.


METHODS
Filipin staining, forskolin-stimulated anion efflux and FITC-dextran uptake were studied in control cells and fibroblasts treated with 2-hydroxypropyl beta-cyclodextrin phosphatidylcholine large unilamellar vesicles to deplete cellular free cholesterol.


RESULTS
Treatment of F508delCFTR-, but not wtCFTR-, expressing fibroblasts with 2-hydroxypropyl beta-cyclodextrin resulted in a reduction in cellular cholesterol and a potentiation of the forskolin-induced anion efflux. In addition, forskolin also promoted a massive increase in the rate of endocytosis in F508delCFTR fibroblasts, which was absent in genistein- or cyclodextrin-treated cultures.


CONCLUSIONS
The results not only suggest that reducing cellular cholesterol may serve as pharmacotherapeutic tool in the treatment of cystic fibrosis but also reveal a novel mechanism for genistein regulation of F508delCFTR, i.e. retention by inhibition of endocytosis.
Lim
Christina H
CH
Department of Biochemistry, Erasmus University Medical Center, Rotterdam, The Netherlands.
Bijvelds
Marcel J
MJ
Nigg
Alex
A
Schoonderwoerd
Kees
K
Houtsmuller
Adriaan B
AB
de Jonge
Hugo R
HR
Tilly
Ben C
BC
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism / Q000494:pharmacology*; D005576:Colforsin / Q000494:pharmacology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D010649:Phenylalanine / Q000235:genetics / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000494:pharmacology
D010713:Phosphatidylcholines; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D005576:Colforsin; D010649:Phenylalanine; D002784:Cholesterol; D019833:Genistein