Bioinspired Star-Shaped Poly(l-lysine) Polypeptides: Efficient Polymeric Nanocarriers for the Delivery of DNA to Mesenchymal Stem Cells

• DOI: 10.1021/acs.molpharmaceut.8b00044
• Publication Date: 2018-03-29T01:47:13Z
• Authors: David P. Walsh; Robert D. Murphy; Angela Panarella; Rosanne M. Raftery; Brenton Cavanagh; Jeremy C. Simpson; Fergal J. O’Brien; Andreas Heise; Sally-Ann Cryan
• Keywords: Drug Carriers; Tissue Engineering; Polymers; Genetic Vectors; Gene Transfer Techniques; Bone Morphogenetic Protein 2; Mesenchymal Stem Cells; DNA; Genetic Therapy; 01 natural sciences; Clathrin; Rats; 0104 chemical sciences; Drug Delivery Systems; Genes, Reporter; Nucleic Acids; Animals; Nanoparticles; Polyethyleneimine; Polylysine; Peptides; Cells, Cultured

The field of tissue engineering is increasingly recognizing that gene therapy can be employed for modulating in vivo cellular response thereby guiding tissue regeneration. However, the field lacks a versatile and biocompatible gene delivery platform capable of efficiently delivering transgenes to mesenchymal stem cells (MSCs), a cell type often refractory to transfection. Herein, we describe the extensive and systematic exploration of three architectural variations of star-shaped poly(l-lysine) polypeptide (star-PLL) with varying number and length of poly(l-lysine) arms as potential nonviral gene delivery vectors for MSCs. We demonstrate that star-PLL vectors are capable of self-assembling with pDNA to form stable, cationic nanomedicines. Utilizing high content screening, live cell imaging, and mechanistic uptake studies we confirm the intracellular delivery of pDNA by star-PLLs to MSCs is a rapid process, which likely proceeds via a clathrin-independent mechanism. We identify a star-PLL composition with 64 poly(l-lysine) arms and five l-lysine subunits per arm as a particularly efficient vector that is capable of delivering both reporter genes and the therapeutic transgenes bone morphogenetic protein-2 and vascular endothelial growth factor to MSCs. This composition facilitated a 1000-fold increase in transgene expression in MSCs compared to its linear analogue, linear poly(l-lysine). Furthermore, it demonstrated comparable transgene expression to the widely used vector polyethylenimine using a lower pDNA dose with significantly less cytotoxicity. Overall, this study illustrates the ability of the star-PLL vectors to facilitate efficient, nontoxic nucleic acid delivery to MSCs thereby functioning as an innovative nanomedicine platform for tissue engineering applications.