Heparin can improve the viability of transfected cystic fibrosis cell lines in vitro

Cell culture models demonstrate that CFTR dysfunction leads to defective fatty acid composition and metabolism

Cystic fibrosis (CF) is associated with fatty acid alterations characterized by low linoleic and docosahexaenoic acid. It is not clear whether these fatty acid alterations are directly linked to cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction or result from nutrient malabsorption. We hypothesized that if fatty acid alterations are a result of CFTR dysfunction, those alterations should be demonstrable in CF cell culture models. Two CF airway epithelial cell lines were used: 16HBE, sense and antisense CFTR cells, and C38/IB3-1 cells. Wild-type (WT) and CF cells were cultured in 10% fetal bovine serum (FBS) or 10% horse serum. Fatty acid levels were analyzed by GC-MS. Culture of both WT and CF cells in FBS resulted in very low linoleic acid levels. When cells were cultured in horse serum containing concentrations of linoleic acid matching those found in human plasma, physiological levels of linoleic acid were obtained and fatty acid alterations characteristic of CF tissues were then evident in CF compared with WT cells. Kinetic studies with radiolabeled linoleic acid demonstrated in CF cells increased conversion to longer and more-desaturated fatty acids such as arachidonic acid. In conclusion, these data demonstrate that CFTR dysfunction is associated with altered fatty acid metabolism in cultured airway epithelial cells.

Enhanced cellular delivery and transfection efficiency of plasmid DNA using positively charged biocompatible colloidal gold nanoparticles

Efficient and safe nonviral gene delivery systems are a prerequisite for the clinical application of therapeutic genes. In this study, we report an enhancement of the transfection efficiency of plasmid DNA, via the use of positively charged colloidal gold nanoparticles (PGN). Plasmid DNA encoding for murine interleukin-2 (pVAXmIL-2) was complexed with PGN at a variety of ratios. The delivery of pVAXmIL-2 into C2C12 cells was dependent on the complexation ratios between PGN and the plasmid DNA, presented the highest delivery at a ratio of 2400:1. After complexation with DNA, PGN showed significantly higher cellular delivery and transfection efficiency than did the polyethylenimines (PEI) of different molecular weights, such as PEI25K (m.w. 25 kd) and PEI2K (m.w. 2 kd). PGN resulted in a cellular delivery of pVAXmIL-2 6.3-fold higher than was seen with PEI25K. The PGN/DNA complex resulted in 3.2- and 2.1-fold higher murine IL-2 protein expression than was seen in association with the PEI25K/DNA and PEI2K/DNA complexes, respectively. Following intramuscular administration, PGN/DNA complexes showed more than 4 orders of magnitude higher expression levels as compared to naked DNA. Moreover, the PGN/DNA complexes showed higher cell viability than other cationic nonviral vectors. Collectively, the results of this study suggest that the PGN/DNA complexes may harbor the potential for development into efficient and safe gene delivery vehicles.

Towards an in vitro model of cystic fibrosis small airway epithelium: characterisation of the human bronchial epithelial cell line CFBE41o-

The CFBE41o- cell line was generated by transformation of cystic fibrosis (CF) tracheo-bronchial cells with SV40 and has been reported to be homozygous for the DeltaF508 mutation. A systematic characterisation of these cells, which however, is a pre-requisite for their use as an in vitro model, has not been undertaken so far. Here, we report an assessment of optimal culture conditions, the expression pattern of drug-transport-related proteins and the stability/presence of the CF transmembrane conductance regulator (CFTR) mutation in the gene and gene product over multiple passages. The CFBE41o- cell line was also compared with a wild-type airway epithelial cell line, 16HBE14o-, which served as model for bronchial epithelial cells in situ. The CFBE41o- cell line retains at least some aspects of human CF bronchial epithelial cells, such as the ability to form electrically tight cell layers with functional cell-cell contacts, when grown under immersed (but not air-interfaced) culture conditions. The cell line is homozygous for DeltaF508-CFTR over multiple passages in culture and expresses a number of proteins relevant for pulmonary drug absorption (e.g. P-gp, LRP and caveolin-1). Hence, the CFBE41o- cell line should be useful for studies of CF gene transfer or alternative treatment with small drug molecules and for the gathering of further information about the disease at the cellular level, without the need for primary culture.