A Powerful Nonviral Vector for In Vivo Gene Transfer into the Adult Mammalian Brain: Polyethylenimine

Abstract

Nonviral gene transfer into the central nervous system (CNS) offers the prospect of providing safe therapies for neurological disorders and manipulating gene expression for studying neuronal function. However, results reported so far have been disappointing. We show that the cationic polymer polyethylenimine (PEI) provides unprecedentedly high levels of transgene expression in the mature mouse brain. Three different preparations of PEI (25-, 50-, and 800-kD) were compared for their transfection efficiencies in the brains of adult mice. The highest levels of transfection were obtained with the 25-kD polymer. With this preparation, DNA/PEI complexes bearing mean ionic charge ratios closest to neutrality gave the best results. Under such conditions, and using a cytomegalovirus (CMV)-luciferase construction, we obtained up to 0.4 10(6) RLU/microgram DNA (equivalent to 0.4 ng of luciferase), which is close to the values obtained using PEI to transfect neuronal cultures and the more easily transfected newborn mouse brain (10(6) RLU/microgram DNA). Widespread expression (over 6 mm3) of marker (luciferase) or functional genes (bcl2) was obtained in neurons and glia after injection into the cerebral cortex, hippocampus, and hypothalamus. Transgene expression was found more than 3 months post-injection in cortical neurons. No morbidity was observed with any of the preparations used. Thus, PEI, a low-toxicity vector, appears to have potential for fundamental research and genetic therapy of the brain.

The Shb signalling scaffold binds to and regulates constitutive signals from the Epstein–Barr virus LMP2A membrane protein

“…For protein expression in HEK 293 cells, 5 Â 10 6 -1 Â 10 7 cells in 85 mm plates were transfected with 5-10 mg plasmid DNA by a modified PEI technique (Abdallah et al, 1996) using 25 kDa polyethyleneimine (PEI, Aldrich cat. 40,872-7, Sigma Aldrich Chemie GmbH, Steinheim, Germany).…”

Dextran–spermine polycation: an efficient nonviral vector for in vitro and in vivo gene transfection

“…8,9 Polycations used for gene complexation are polyamines that become cationic at physiologic conditions. The most studied polycations used for gene complexation and delivery are the branched/linear polyethylene imine (PEI), 10,11 poly(L-lysine), 12 poly (dimethyl aminoethyl methacrylate, pDMAEMA), 13 poly(trimethyl aminoethyl methacrylate, pTMAEMA), 14 poly(vinylpyridine), 15 chitosan, 16 and diethylaminoethyl dextran (DEAE-dextran). 17 Most polycations are toxic to cells and nonbiodegradable, while the polymers based on amino acids such as poly(lysine) are immunogenic.…”

Delivery of unmodified bioactive ribozymes by an RNA-stabilizing polyethylenimine (LMW-PEI) efficiently down-regulates gene expression

“…13,14 Commercially available high molecular weight (HMW) PEIs (25-800 kDa) are able to deliver large DNA molecules such as 2.3 Mb yeast artificial chromosomes (Yaks) 15 as well as plasmids or small oligonucleotides 13,[16][17][18] into mammalian cells in vitro and in vivo. This function as a potent transfection reagent relies on the PEI's ability to condense and compact the carried DNA into complexes, which form small colloidal particles allowing efficient cellular uptake through endocytosis.…”