Yixiao Zhang1 Ki-Bum Lee1

1, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States

Stem cell reprogramming and therapies have shown tremendous significance and potential in the field of regenerative medicine and tissue engineering. Therefore, developing tools to control stem cell fate is an attractive area of research for replacing damaged and diseased cells and re-establishing functional recovery for tissue/organ repair. Transcription factors (TFs) are multi-domain proteins that play a critical role in orchestrating stem cell differentiation and direct conversion. Previously, our group developed a highly tunable and versatile platform, named NanoScript, which is designed to mimic functions of TFs to bind to specific portions of the genome and regulate gene expression in a way that does not involve viral delivery. We have demonstrated that the NanoScript platform can upregulate targeted endogenous genes in a nonviral manner. Furthermore, we modified and utilized the tunable property of NanoScript to mimic differentiation-specific factors and activate related genes to induce stem cell differentiation. Apart from gene activation, we successfully demonstrated neuronal differentiation from neural stem cells through Sox-9 repression using NanoScript designed with Sox-9 specific polyamide and a repressor peptide.
Although there are various applications of NanoScript demonstrated by our group in stem cell differentiation and regenerative medicine, the lack of degradability hinders NanoScript from moving into in vivo applications and translational researches. As a result, we have designed a polymer micelle system based on polypeptides to renovate and improve the previous version of NanoScript. By carefully design and modulate the polypeptide polymer micelle structure, this newer version of NanoScript possesses small molecule, oligo-nucleotide and metal ion loading capacity. As a first demonstration, this new generation of polypeptide-based NanoScript was functionalized and designed to regulate skeletal muscle cell differentiation from adipose-derived mesenchymal stem cells (ADSCs) by targeting myogenic regulatory factors (MRFs), which play an important role in inducing myogenesis and skeletal muscle lineage commitment. This polypeptide-based NanoScript is stable in physiological environments, showing high nuclear localization rate, as well as inducing differentiation of ADSCs into mature myocytes in 1 week. As such, this peptide-based NanoScript can be a safe and powerful gene modulation tool for various applications in stem cell therapy and tissue regeneration.
[1] Patel, S.; Jung, D.; Yin, P.T.; Carlton, P.; Yamamoto, M.; Bando, T.; Sugiyama, H.; Lee, K-.B., “NanoScript: A Nanoparticle-Based Artificial Transcription Factor for Effective Gene Regulation”, ACS Nano, 2014, 9, 8959-8967
[2] Dardir, K.; Rathnam, C; Lee, K.-B., “NanoScript: A Versatile Nanoparticle-Based Synthetic Transcription Factor for Innovative Gene Manipulation”, Biomedical Nanotechnology. Methods in Molecular Biology, 2017, 1570, 239-249