Intracellular Delivery of Transcription Factors Using Polymeric Nanocapsules

Transcription factors have the unique ability to regulate gene expression and thus determine cellular fate. Intracellular delivery of transcription factors has important therapeutic implications and can be a mode to treat loss-of-function diseases or initiate cellular reprogramming. DNA-based methods raise safety concerns because of the potential for unexpected genetic modifications by exogenous sequences in target cells. From a therapeutic perspective, protein-based approaches are safer than gene therapy because no random or permanent genetic changes are involved, and only transient actions of proteins are needed for the desired results. We have developed degradable polymeric nanocapsules (NCs) which can release encapsulated cargo intracellularly in active form. Nuclear proteins were encapsulated in NCs synthesized with monomers and either endoprotease-degradable or redox-responsive crosslinkers. Release of cargo was demonstrated successfully in vitro and elucidated the importance of the degradability of the nanocapsules for observed nuclear localization. To demonstrate delivery of biologically relevant nuclear cargos, we have prepared NCs encapsulating transcription factors relevant to cellular reprogramming and differentiation. We show that these transcription factors delivered via NCs show enhanced nuclear localization compared to those delivered via protein transduction domains. We also demonstrate that NC-delivered proteins are able to deliver active proteins through functional biological assays based on the specific activity of the transcription factors. This degradable polymeric nanocapsule intracellular delivery system may be generalized to effectively deliver many biological components.