Abstract
Hepatic uptake and gene expression mechanisms following intravenous administration of naked plasmid DNA (pDNA) by conventional and hydrodynamics-based procedures were studied in mice. After conventional (normal) intravenous injection, 32P-labeled pDNA was rapidly eliminated from the circulation and predominantly taken up by the liver nonparenchymal cells while no significant gene expression was observed in this organ. The hepatic uptake process was saturable. Involvement of a specific mechanism was demonstrated since the hepatic uptake of [32P]pDNA was dramatically inhibited by cold pDNA, calf thymus DNA, and some polyanions [polyinosinic acid (poly I), dextran sulfate], but not by others (polycytidylic acid, chondroitin sulfate). The liver endothelial cells appeared to be a major contributor because gadolinium chloride (GdCl3)-induced Kupffer cell blockade did not affect the hepatic uptake. After intravenous injection of naked pDNA with a large volume of saline at a high velocity (hydrodynamics-based procedure), the apparent hepatic uptake profile was similar to that after normal injection. The hepatic uptake was not inhibited by prior administration of polyanions, including poly I, dextran sulfate, and heparin. The hydrodynamics-based procedure resulted in marked gene expression in the liver, which was not inhibited by prior administration of polyanions or GdCl3 treatment. These results indicate that pDNA uptake is a nonspecific process. This hypothesis was supported by the finding that significant hepatic uptake of bovine serum albumin and immunoglobulin G was observed after the hydrodynamics-based procedure.
Footnotes
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Send reprint requests to: Yoshinobu Takakura, Ph.D., Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan. E-mail: takakura{at}pharm.kyoto-u.ac.jp
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This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture, Japan.
- Abbreviations:
- pDNA
- plasmid DNA
- NPC
- nonparenchymal cells
- PEG4000
- polyethylene glycol with molecular weight of 4000
- poly I
- polyinosinic acid
- poly C
- polycytidylic acid
- In
- indium
- BSA
- bovine serum albumin
- AUC
- the area under plasma concentration-time curve
- Man-Liposome
- mannosylated liposome
- Man-BSA
- mannosylated bovine serum albumin
- Received December 4, 2000.
- Accepted March 1, 2001.
- The American Society for Pharmacology and Experimental Therapeutics
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