Nakamura M, Davila-Zavala P, Tokuda H, Takakura Y, Hashida M
Department of Drug Delivery Research, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Sakyo-ku, 606-8501, Japan.
Biochem Biophys Res Commun. 1998 Apr 7;245(1):235-9. doi: 10.1006/bbrc.1998.8334.
Cellular uptake and gene expression of plasmid DNA and its cationic liposome complexes were studied using primary cultures of bovine brain microvessel endothelial cells (BMEC) developed as an in vitro model of the blood-brain barrier. An avid association of naked plasmid DNA with the BMEC monolayer was observed at 37 degreesC, which is comparable to that of the DNA/liposome complex. The cellular association significantly decreased at low temperature (4 degreesC). The binding at 4 degreesC was saturable and significantly inhibited by polyanions involving polyinosinic acid and dextran sulfate, typical ligands for the macrophage scavenger receptors, but not by polycytidylic acid or in the presence of EDTA. Unexpectedly, a significant gene expression in the BMEC was obtained by transfection with naked plasmid DNA although the expression level was lower than that obtained by plasmid DNA/cationic liposome complex. Taken together, cultured capillary endothelial cells derived from the brain are able to take up naked plasmid DNA via a scavenger receptor like-mediated mechanism for polyanions and gene expression in the cells takes place.
利用作为血脑屏障体外模型构建的牛脑微血管内皮细胞（BMEC）原代培养物，研究了质粒DNA及其阳离子脂质体复合物的细胞摄取和基因表达。在37℃观察到裸质粒DNA与BMEC单层有强烈结合，这与DNA/脂质体复合物的结合情况相当。在低温（4℃）下，细胞结合显著减少。4℃时的结合是可饱和的，且被涉及多聚肌苷酸和硫酸葡聚糖的多阴离子显著抑制，这两种物质是巨噬细胞清道夫受体的典型配体，但不受聚胞苷酸抑制，也不受EDTA存在的影响。出乎意料的是，通过用裸质粒DNA转染在BMEC中获得了显著的基因表达，尽管表达水平低于通过质粒DNA/阳离子脂质体复合物获得的表达水平。综上所述，源自脑的培养毛细血管内皮细胞能够通过类似清道夫受体介导的多阴离子摄取机制摄取裸质粒DNA，并且细胞内发生基因表达。
