INFLUENCE OF CELL POLARITY ON RETROVIRUS-MEDIATED GENE-TRANSFER TO DIFFERENTIATED HUMAN AIRWAY EPITHELIA

Gene transfer with recombinant murine leukemia viruses (MuLV) provides the potential to permanently correct inherited lung diseases, such as cystic fibrosis (CF). Several problems prevent the application of MuL V-based recombinant retroviruses to lung gene therapy: (i) the lack of cell proliferation in mature pulmonary epithelia, (ii) inefficient ge ne transfer with a vector applied to the apical surface, and (iii) low titers of many retroviral preparations. We found that keratinocyte gr owth factor (KGF) stimulated proliferation of differentiated human tra cheal and bronchial epithelia. Approximately 50% of epithelia divided in response to KGF as assessed by bromodeoxyuridine histochemistry. In airway epithelia stimulated to divide with KGF, high-titer ampho- and xenotropic enveloped vectors preferentially infected cells from the b asal side. However, treatment with hypotonic shock or EGTA transiently increased transepithelial permeability, enhancing gene transfer with the vector applied to the mucosal surfaces of KGF-stimulated epithelia . Up to 35% of cells expressed the transgene after gene transfer. By u sing this approach, cells throughout the epithelial sheet, including b asal cells, were targeted. Moreover, the Cl- transport defect in diffe rentiated CF airway epithelia was corrected. These findings suggest th at barriers to apical infection with MuLV can be overcome.