Enhanced lipoplex-mediated gene expression in mesenchymal stem cells using reiterated nuclear localization sequence peptides

Background Mesenchymal stem cells (MSC) are widely regarded as a promising tool for cellular therapy applications, and genetic modification by safe, liposome-based vectors may enhance their therapeutic potential. Methods The present study describes the use of a cationic lipid vector (Lipofectamine 2000 (TM)) to deliver genes to MSC isolated from a number of species in vitro and determined the characteristics of this vector system in terms of dose, toxicity and the time course of expression. In addition, the optimal use of a nuclear localization sequence (NLS) to enhance gene expression was explored. Results Lipofection of human MSC did not adversely affect their ability to differentiate into osteogenic- and adipogenic lineages. Although human and rat MSC were found to take up lipoplexes with relative efficiency, lower levels of gene expression were detected in rabbit MSC, demonstrating a crucial effect of species. Peptides containing reiterated motifs of NLS were found to significantly improve on the level of transgene expression. Optimal gene delivery was observed when a three-fold reiterated NLS sequence was included in the liposome formulation. Conclusions Thus, nonviral gene delivery to MSC is feasible with efficiency being species dependent and can be enhanced by use of a three-fold reiterated NLS. Copyright (C) 2010 John Wiley & Sons, Ltd.