Liposome-mediated Transfer of Simian Virus 40 DNA and Minichromosome into Mammalian Cells

Abstract

SUMMARYWe have investigated the use of liposomes as carriers for the transfer of simian virus 40 (SV40) DNA into mammalian cells. The amount of DNA entrapped in liposomes was dependent on the input DNA concentration and lipid composition. DNA remained intact after liposome encapsulation and was resistant to deoxyribonuclease digestion. Combined transfer to and expression of liposome-entrapped SV40 DNA in monkey kidney cells was assayed by infectious plaque formation. Negatively-charged liposomes containing phosphatidylserine were more effective in DNA transfer and expression than neutral liposomes. The inclusion of carrier salmon sperm DNA inhibited liposome-entrapped SV40 DNA infectivity. Infectivity of liposomeentrapped DNA was directly related to both liposome DNA concentration and number of vesicles added. Liposome-entrapped SV40 minichromosome was 20-fold more infective than free minichromosome, but only 20% more infective than liposomeentrapped SV40 DNA. Thus, the presence of hyperacetylated histones on the DNA failed to enhance liposome-mediated DNA transfer appreciably. Incubation of cells with various modulators of endocytosis implicated the endocytotic pathway in the mechanism of liposome-mediated DNA transfer. These studies show that liposomes are suitable carriers for the introduction of viral DNA and chromatin into mammalian cells.

Use of virus-attached antibodies or insulin molecules to mediate fusion between Sendai virus envelopes and neuraminidase-treated cells

“…RSVE fuse with cell plasma membranes, thus injecting their content directly into the cell cytoplasm or inserting their membrane components into recipient cell membranes. Liposomes, on the other hand, are taken into cells by endocytosis (Pagano & Weinstein, 1978), and in many cases, their use requires the addition of poly(ethylene glycol) (Doyle et al, 1979) or glycerol (Rizzo et al, 1983), both of which affect cell viability. However, loaded liposomes have been shown to be able to carry their content into tissues of whole animals (Chapman et al, 1984).…”

Enhancement of Wound Healing in Normal and Diabetic Mice by Topical Application of Amorphous Polyphosphate. Superior Effect of a Host–Guest Composite Material Composed of Collagen (Host) and Polyphosphate (Guest)

“…Since in the present study the size of the particles supplied to the cells is larger than the preferred particle size for the endocytic uptake machinery we postulate that only after ALP-mediated degradation of the microparticles are the nanoparticles generated taken up by the cells. In consideration of transfection studies it is established that the highly negatively charged DNA, like polyP, can be readily taken up by mammalian cells if entrapped into less charged particles, like liposomes [46]. Building on the presented in vitro and in vivo data we propose further safety studies in animals that might be followed by first human trials.…”

Highly efficient DNA delivery mediated by pH-sensitive immunoliposomes

“…This method is quite mild, and the resulting liposomes are quite large in size {d > 0.1 µ ) (Papahadjopoulos et al, 1975). The reverse-phase evaporation method (Szoka & Papahadjopoulos, 1978) is also commonly used for entrapping DNA (Schaefer et al, 1982;Rizzo et al, 1983;Machy et al, 1988;Fraley et al, 1981). We have used a detergent dialysis method which has been shown to also entrap large amounts of nucleic acid (Philippot et al, 1983).…”