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Non-viral gene delivery to mesenchymal stem cells: methods, strategies and application in bone tissue engineering and regeneration

Publication . Santos, José L.; Pandita, Deepti; Rodrigues, João; Pêgo, Ana P.; Granja, Pedro L.; Tomás, Helena

Mesenchymal stem cells (MSCs) can be isolated from several tissues in the body, have the ability to selfrenewal, show immune suppressive properties and are multipotent, being able to generate various cell types. At present, due to their intrinsic characteristics, MSCs are considered very promising in the area of tissue engineering and regenerative medicine. In this context, genetic modification can be a powerful tool to control the behavior and fate of these cells and be used in the design of new cellular therapies. Viral systems are very effective in the introduction of exogenous genes inside MSCs. However, the risks associated with their use are leading to an increasing search for non-viral approaches to attain the same purpose, even if MSCs have been shown to be more difficult to transfect in this way. In the past few years, progress was made in the development of chemical and physical methods for non-viral gene delivery. Herein, an overview of the application of those methods specifically to MSCs is given and their use in tissue engineering and regenerative medicine therapeutic strategies highlighted using the example of bone tissue. Key issues and future directions in non-viral gene delivery to MSCs are also critically addressed.

2011Journal article

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Osteogenic differentiation of mesenchymal stem cells using PAMAM dendrimers as gene delivery vectors

Publication . Santos, José Luís; Oramas, Elena; Pêgo, Ana Paula; Granja, Pedro Lopes; Tomás, Helena

This paper reports the use of different generations of polyamidoamine (PAMAM) dendrimers for the in vitro transfection of mesenchymal stem cells (MSCs). A systematic study was carried out on the transfection efficiency achieved by the PAMAM dendrimers using a beta-galactosidase reporter gene system. Transfection results were shown to be dependent upon the generation of dendrimers, the amine to phosphate group ratio and the cell passage number. In all cases, the transfection efficiency was very low. Nevertheless, it was hypothesized that a low transfection level could be sufficient to promote the in vitro differentiation of MSCs towards the osteoblastic lineage. To address this possibility, dendrimers carrying the human bone morphogenetic protein-2 (hBMP-2) gene-containing plasmid were used. All quantitative (alkaline phosphatase activity, osteocalcin secretion and calcium deposition) and qualitative (von Kossa staining) osteogenic markers were significantly stronger in transfected cells when compared to non-transfected ones. This study not only clearly demonstrates that a low transfection level can be sufficient for inducing in vitro differentiation of MSCs to the osteoblast phenotype but also highlights the importance of focusing research on the development of gene delivery vectors in the concrete application.

2009Journal article

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