Transgene Expression in Mouse Airway Epithelium by Aerosol Gene Therapy with PEI–DNA Complexes

Abstract

Gene therapy targeted at the respiratory epithelium holds therapeutic potential for diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency. A variety of approaches such as intranasal or intratracheal instillation and aerosol delivery have been utilized to target genes to the airways. Polyethylenimine (PEI), a linear or branched polycationic polymer, has been used for delivery of genes to various organs. In this study, using fluorescein isothiocyanate (FITC)-labeled branched PEI, we initially examined the localization of PEI in the lungs after aerosol delivery to Balb/C mice. Further, after aerosol delivery of PEI-CAT DNA, in situ immunostaining for chloramphenicol acetyl transferase (CAT) protein was used to localize the transgene expression within the lungs. Immunohistochemistry for CAT, as well as localization of FITC-labeled PEI, revealed that after aerosol delivery, the PEI-DNA complexes deposit and subsequently transfect most of the epithelial cells in the conducting airways (including the peripheral airways). High levels of CAT were detected at 24 h after aerosol exposure and significant CAT expression was detected in the lungs up to 28 days after a single aerosol exposure. The data suggest that aerosol delivery of PEI-DNA complexes could be effective for the treatment of pulmonary diseases such as cystic fibrosis and alpha-1 anti-trypsin deficiency.

Growth suppression of established human osteosarcoma lung metastases in mice by aerosol gene therapy with PEI– p53 complexes

“…One possibility is because of the long -term expression of CAT (about a month ), which could have some growth inhibitory effect. 18 In addition to the results achieved here with p53 and the nude mouse osteosarcoma lung metastases model, we have also shown previously that aerosolized PEI formulations of p53 results in a significant antitumor response and extended survival in a murine melanoma ( B16 -F10 melanoma in C57 BL / 6 mice) model. 7 These two models differ considerably.…”

“…A detailed description of the deposition of aerosolized PEI and transgene expression in the lungs is described elsewhere. 18 Anticancer studies reported here showed that aerosol delivery of p53wt and the synthetic p53 variant CD -1 caused a significant reduction in lung metastases in a nude mouse model of osteosarcoma. The lung weights and tumor burden for the p53-treated groups were significantly reduced when compared to untreated mice as well as to mice treated with PEI alone or with PEI -pCMVCAT.…”

“…19 This lack of a CpG effect may help to explain why we have found that repeated aerosol exposures to PEI -DNA result in a sustained transgene expression in the lungs over a period of time. 18 The significant antitumor response against SAOS -LM6 tumors in nude mice, which exhibit a reduced immune response, is further evidence of a specific p53 antitumor effect.…”

“…This is similar to the expression of aerosol-delivered PEI -CAT. 18 Suppression of SAOS -LM6 lung metastases by aerosol delivery of PEI -p53 and PEI -p53CD( 1 -366 )…”

Fatty acid–spermine conjugates as DNA carriers for nonviral in vivo gene delivery

“…[36][37][38] The most successful cases occur after intranasal or intratracheal administration, when targeting airway epithelial cells. 3,5,9,39 Tissues containing nondividing cells (as in muscle) or slow mitotic cells (as in the liver) are very attractive targets because pDNA can remain for a long time inside the cells. 40 In relation to the relatively fast kinetics seen here, we do not exclude the possibility that the decrease in expression after 5-7 days may be indicative of toxicity.…”