Nonviral gene transfer into fetal mouse livers (a comparison between the cationic polymer PEI and naked DNA).
We investigated the efficacy and safety of the cationic polymer polyethylenimine (PEI) as a potential tool for intrauterine gene delivery into livers of fetal mice in the last trimester of pregnancy (E17.5). Using luciferase as a reporter gene, transferrin-conjugated and ligand-free PEI/DNA complexes (containing 3 microg DNA) with varying PEI-nitrogen/DNA-phosphate (N/P) ratios and different PEI forms, branched (800, 25 kDa) and linear (22 kDa), were compared with naked DNA. Transgene expression was measured 48 h after administration of PEI/DNA complexes or naked DNA. Highest luciferase activity (9.8 x 10(3) relative light units (RLU)/mg of tissue protein) was observed with ligand-free PEI22/DNA mixtures at N/P 6.0. In addition, this formulation was associated with very low toxicity as compared to the other PEI/DNA-injected groups. Using beta-galactosidase as a reporter gene, transfection of single, but also small, clusters of cells was demonstrated throughout the liver. Injection of 3 microg naked DNA resulted in an 11-fold lower transgene expression value (0.9 x 10(3) RLU/mg of tissue protein) as compared to PEI22/DNA complexes. However, the administration of higher concentrated naked DNA (9 microg) into fetal livers yielded expression levels of 3.2 x 10(4) RLU/mg of tissue protein, a more than three-fold increase compared to PEI22/DNA complexes. Furthermore, the gene transfer efficacy of concentrated naked DNA was approximately 40 times higher in fetuses than in adults (0.8 x 10(3) RLU/mg of tissue protein), indicating that fetal tissue is especially amenable to the uptake and expression of naked DNA.
Gharwan
H
H
Institute of Pathology, University of Graz, Auenbruggerplatz, Graz, Styria, Austria.
Wightman
L
L
Kircheis
R
R
Wagner
E
E
Zatloukal
K
K
D016475:3T3 Cells; D000818:Animals; D000831:Animals, Newborn; D004247:DNA / Q000008:administration & dosage*; D005260:Female; D005315:Fetal Diseases / Q000628:therapy*; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D008099:Liver / Q000196:embryology* / Q000378:metabolism*; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D051379:Mice; D008808:Mice, Inbred CBA; D008854:Microscopy, Electron; D011094:Polyethyleneimine; D014018:Tissue Distribution; D014162:Transfection / Q000379:methods*
D011094:Polyethyleneimine; D004247:DNA; D008156:Luciferases