Low molecular weight polyethylenimine for efficient transfection of human hematopoietic and umbilical cord blood-derived CD34+ cells

With the emerging role of hematopoictic stem cells as potential gene and cell therapy vehicles, there is an increasing need for safe and effective nonviral gene delivery systems. Here, we report that gene transfer and transfection efficiency in human hematopoietic and cord blood CD34(+) cells can be enhanced by the use of low molecular weight polyethylenimine (PEI). PEls of various molecular weights (800750,000) were tested, and our results showed that the uptake of plasmid DNA by hematopoietic TF-1 cells depended on the molecular weights and the N/P ratios. Treatment with PEI 2 K (m.w. 2000) at an N/P ratio of 80/1 was most effective, increasing the uptake of plasmid DNA in TF-1 cells by 23-fold relative to Lipofectamine 2000. PEI 2 K-enhanced transfection was similarly observed in hematopoietic K562, murine Sca-1(+), and human cord blood CD34(+) cells. Notably, in human CD34(+) cells, a model gene transferred with PEI 2 K showed 21,043- and 513-fold higher mRNA expression levels relative to the same construct transfected without PEI or with PEI 25 K, respectively. Moreover, PEI 2 K-treated TF-1 and human CD34(+) cells retained good viability. Collectively, these results indicate that PEI 2 K at the optimal N/P ratio might be used to safely enhance gene delivery and transfection of hematopoietic and human CD34(+) stem cells. (c) 2005 Elsevier B.V. All rights reserved.