CFTR delivery to 25% of surface epithelial cells restores normal rates of mucus transport to human cystic fibrosis airway epithelium.
Dysfunction of CFTR in cystic fibrosis (CF) airway epithelium perturbs the normal regulation of ion transport, leading to a reduced volume of airway surface liquid (ASL), mucus dehydration, decreased mucus transport, and mucus plugging of the airways. CFTR is normally expressed in ciliated epithelial cells of the surface and submucosal gland ductal epithelium and submucosal gland acinar cells. Critical questions for the development of gene transfer strategies for CF airway disease are what airway regions require CFTR function and how many epithelial cells require CFTR expression to restore normal ASL volume regulation and mucus transport to CF airway epithelium? An in vitro model of human CF ciliated surface airway epithelium (CF HAE) was used to test whether a human parainfluenza virus (PIV) vector engineered to express CFTR (PIVCFTR) could deliver sufficient CFTR to CF HAE to restore mucus transport, thus correcting the CF phenotype. PIVCFTR delivered CFTR to >60% of airway surface epithelial cells and expressed CFTR protein in CF HAE approximately 100-fold over endogenous levels in non-CF HAE. This efficiency of CFTR delivery fully corrected the basic bioelectric defects of Cl(-) and Na(+) epithelial ion transport and restored ASL volume regulation and mucus transport to levels approaching those of non-CF HAE. To determine the numbers of CF HAE surface epithelial cells required to express CFTR for restoration of mucus transport to normal levels, different amounts of PIVCFTR were used to express CFTR in 3%-65% of the surface epithelial cells of CF HAE and correlated to increasing ASL volumes and mucus transport rates. These data demonstrate for the first time, to our knowledge, that restoration of normal mucus transport rates in CF HAE was achieved after CFTR delivery to 25% of surface epithelial cells. In vivo experimentation in appropriate models will be required to determine what level of mucus transport will afford clinical benefit to CF patients, but we predict that a future goal for corrective gene transfer to the CF human airways in vivo would attempt to target at least 25% of surface epithelial cells to achieve mucus transport rates comparable to those in non-CF airways.
Zhang
Liqun
L
CF/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Button
Brian
B
Gabriel
Sherif E
SE
Burkett
Susan
S
Yan
Yu
Y
Skiadopoulos
Mario H
MH
Dang
Yan Li
YL
Vogel
Leatrice N
LN
McKay
Tristan
T
Mengos
April
A
Boucher
Richard C
RC
Collins
Peter L
PL
Pickles
Raymond J
RJ
D000704:Analysis of Variance; D001692:Biological Transport / Q000502:physiology; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism*; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D009093:Mucus / Q000378:metabolism*; D010222:Parainfluenza Virus 1, Human / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000378:metabolism
C505032:CFTR protein, human; D002712:Chlorides; D011993:Recombinant Fusion Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D049452:Green Fluorescent Proteins; D012964:Sodium