Efficiency of gene transfer for restoration of normal airway epithelial function in cystic fibrosis

Abstract

An important issue for in vivo gene therapy for cystic fibrosis (CF) is the percentage of cells within the CF airway that will require correction. In this study, we mixed populations of a CF airway cell line expressing either the normal cystic fibrosis transmembrane conductance regulator (CFTR) cDNA (corrected cells) or a reporter gene in defined percentages. As few as 6-10% corrected cells within an epithelial sheet generated C1-transport properties similar to sheets comprised of 100% corrected cells. Cell-cell coupling may serve as the mechanism for amplification of the functional effects of corrected cells. These data suggest that in vivo correction of all CF airway cells may not be mandatory.

Poly (D, L-lactide-co-glycolide)/DNA microspheres to facilitate prolonged transgene expression in airway epithelium in vitro, ex vivo and in vivo

“…It is possible that low but sustained levels, rather than high but short-lived levels, of transduced CFTR may be required. It has been suggested, for example, that only 6-10% of cells within a monolayer of CF epithelial cells must be 'corrected' in order to restore normal chloride transport, 19 although the percentage required to correct the sodium transport defect has been shown to be much higher than this. 20 Thus, the optimal strategy for functional correction would probably be to mimic normal expression, that is, to correct as close to 100% of cells as possible at low levels of expression per cell.…”

High-titer recombinant adeno-associated virus production utilizing a recombinant herpes simplex virus type I vector expressing AAV-2 Rep and Cap

“…31 Expression of these immediate-early genes is detrimental to the cell and induces cell death. 49,50 At high MOIs, increased expression of these immediate-early genes probably leads to rapid cell death, limiting the production of rAAV. At a MOI of 25, while there is increased expression of the AAV-2 rep genes and the HSV-1 helper genes necessary for rAAV production, increased cytotoxicity due to additional gene expression from the vector also occurs.…”

The extra- and intracellular barriers to lipid and adenovirus-mediated pulmonary gene transfer in native sheep airway epithelium

“…[1][2][3][4][5][6][7][8] Results have been encouraging, though only limited correction of the CF bioelectric defect has been observed. With respect to the extent of gene transfer needed, a present best estimate might be approximately 5% of normal cystic fibrosis transmembrane conductance regulator (CFTR) mRNA levels within every cell, 9 complete correction of the chloride defect in approximately 5% of cells within the airway epithelium, 10 or likely some combination of the two.…”