Cationic glycopolymers for the delivery of pDNA to human dermal fibroblasts and rat mesenchymal stem cells

Progenitor and pluripotent cell types offer promise as regenerative therapies but transfecting these sensitive cells has proven difficult. Herein, a series of linear trehalose-oligoethyleneamine " click" copolymers were synthesized and examined for their ability to deliver plasmid DNA (pDNA) to two progenitor cell types, human dermal fibroblasts (HDFn) and rat mesenchymal stem cells (RMSC). Seven polymer vehicle analogs were synthesized in which three parameters were systematically varied: the number of secondary amines (4-6) within the polymer repeat unit (Tr4 ₃₃, Tr5 ₃₀, and Tr6 ₃₂), the end group functionalities [PEG (Tr4 ₁₂₈PEG-a, Tr4 ₁₁₈PEG-b), triphenyl (Tr4 ₁₀₇-c), or azido (Tr4 ₉₉-d)], and the molecular weight (degree of polymerization of about 30 or about 100) and the biological efficacy of these vehicles was compared to three controls: Lipofectamine 2000, JetPEI, and Glycofect. The trehalose polymers were all able to bind and compact pDNA polyplexes, and promote pDNA uptake and gene expression [luciferase and enhanced green fluorescent protein (EGFP)] with these primary cell types and the results varied significantly depending on the polymer structure. Interestingly, in both cell types, Tr4 ₃₃ and Tr5 ₃₀ yielded the highest luciferase gene expression. However, when comparing the number of cells transfected with a reporter plasmid encoding enhanced green fluorescent protein, Tr4 ₃₃ and Tr4 ₁₀₇-c yielded the highest number of HDFn cells positive for EGFP. Interestingly, with RMSCs, all of the higher molecular weight analogs (Tr4 ₁₂₈PEG-a, Tr4 ₁₁₈PEG-b, Tr4 ₁₀₇-c, Tr4 ₉₉-d) yielded high percentages of cells positive for EGFP (30-40%).