title: Cystamine-terminated poly(beta-amino ester)s for siRNA delivery to human mesenchymal stem cells and enhancement of osteogenic differentiation.
abstract: Enhancing human mesenchymal stem cell (hMSC) differentiation via RNA interference (RNAi) could provide an effective way of controlling cell fate for tissue engineering, but a safe and effective delivery vehicle must first be developed. Here, we evaluated an array of synthetic end-modified poly(beta-amino ester) (PBAE)-based nanoparticles to optimize siRNA delivery into hMSCs. In general, cystamine-terminated polymers caused the most knockdown, with the best polymer achieving 91% knockdown 20 days post-transfection. Binding studies revealed that the cystamine-terminated polymer bound siRNA tightly at lower weight ratios of polymer to siRNA but then efficiently released siRNA upon exposure to a reducing environment, suggesting that this class of PBAEs can form tight initial interactions with its cargo and then cause efficient, environmentally-triggered release in the cytoplasm. Finally, we tested a functional application of this system by transfecting hMSCs with siRNA against an inhibitor of osteogenesis, B-cell lymphoma (Bcl)-like protein 2 (BCL2L2). This resulted in enhanced osteogenesis over 4 weeks as evidenced by Alizarin Red S staining and calcium quantification. The bioreducible PBAE/siRNA nanoparticles developed here can provide a means of safe and effective control of hMSC differentiation for a wide variety of applications.
authors.affiliation: Department of Biomedical Engineering, Translational Tissue Engineering Center, and Institute for NanoBiotechnology, Johns Hopkins University School of Medicine, 400 N. Broadway, Baltimore, MD 21231, USA.
authors.forename: Stephany Y
authors.initials: SY
authors.lastname: Tzeng
authors.forename: Ben P
authors.initials: BP
authors.lastname: Hung
authors.forename: Warren L
authors.initials: WL
authors.lastname: Grayson
authors.forename: Jordan J
authors.initials: JJ
authors.lastname: Green
mesh_terms: D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D002454:Cell Differentiation; D002460:Cell Line; D003538:Cystamine / Q000031:analogs & derivatives*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry; D010012:Osteogenesis; D011108:Polymers / Q000737:chemistry*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D014161:Transduction, Genetic; D014162:Transfection
chemical_list: D051017:Apoptosis Regulatory Proteins; C491073:BCL2L2 protein, human; D011108:Polymers; D034741:RNA, Small Interfering; C507253:poly(beta-amino ester); D003538:Cystamine