The fate of plasmid DNA after intravenous injection in mice: involvement of scavenger receptors in its hepatic uptake.
OBJECTIVE
We examined the stability and disposition characteristics of a naked plasmid DNA pCAT as a model gene after intravenous injection in mice to construct the strategy of in vivo gene delivery systems.


METHODS
After the injection of pCAT to the mice, stability, tissue distribution, hepatic cellular localization, and effect of some polyanions on the hepatic uptake were studied.


RESULTS
The in vitro study demonstrated that the pCAT was rapidly degraded in mouse whole blood with a half-life of approximately 10 min at a concentration of 100 micrograms/ml. After intravenous injection, pCAT was degraded at a significantly faster rate than that observed in the whole blood, suggesting that pCAT in vivo was also degraded in other compartments. Following intravenous injection of [32P] pCAT, radioactivity was rapidly eliminated from the plasma due to extensive uptake by the liver. Hepatic accumulation occurred preferentially in the non-parenchymal cells. The hepatic uptake of radioactivity derived from [32P] pCAT was inhibited by preceding administration of polyanions such as polyinosinic acid, dextran sulfate, maleylated and succinylated bovine serum albumin but not by polycytidylic acid. These findings indicate that pCAT is taken up by the liver via scavenger receptors on the non-parenchymal cells. Pharmacokinetic analysis revealed that the apparent hepatic uptake clearance was fairly close to the liver plasma flow.


CONCLUSIONS
These findings provide useful information for the development of delivery systems for in vivo gene therapy.
Kawabata
K
K
Department of Drug Delivery Research, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Takakura
Y
Y
Hashida
M
M
D000818:Animals; D004247:DNA / Q000378:metabolism*; D004355:Drug Stability; D015316:Genetic Therapy; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008958:Models, Molecular; D010957:Plasmids / Q000378:metabolism*; D011955:Receptors, Drug; D013997:Time Factors; D014554:Urination
D011955:Receptors, Drug; D004247:DNA