DESCRIPTION: The long-term goal of this application represents the development of novel magnetic core/shell nanoparticles (MCNPs) to deliver and spatiotemporally trigger the differentiation of stem cells to oligodendrocytes. With regard to spinal cord injury, neural stem/progenitor cell (NSPCs) transplantation has been shown to afford a number of favorable therapeutic effects. However, grafted NSPCs were found to differentiate primarily into astrocytes, which tend to hinder the effectiveness of transplantation. The guided differentiation of the grafted NSPCs into oligodendrocytes is highly desirable since these cells provide myelin sheaths around axons and thus enable fast propagation of nerve impulses in the CNS. To this end, the objective is to develop novel MCNPs, which have the dual functions of delivering a plasmid encoding Olig2, which has previously been reported to induce NSPC differentiation to oligodendrocytes, under a heat shock promoter and triggering Olig2 expression through magnetic hyperthermia (i.e. using an alternating magnetic field). To address these challenges, the following specific aims are proposed: Specific Aim 1. To prepare magnetic core/shell nanoparticles and inducible gene vectors for delivery into human induced pluirpotent stem cell-derived neural stem/progenitor cells (hiPSC-derived NSPCs). Specific Aim 2. To test the oligodendrocyte differentiation and remyelination ability of the engineered NSPCs in vitro after magnetic hyperthermia-induced gene expression. Magnetic nanoparticles have previously been applied for MRI, cell targeting, and drug/gene delivery. However, there is a critical gap between the existing knowledge and the clinical application of these nanoparticles to stem cell-based therapy. Therefore, the development of a novel MCNP-based stem cell therapy will demonstrate the multifunctional nature of MNPs for a clinically-relevant SCI treatment. In particular, compared to conventional gene therapies and cellular labeling methodologies, a MCNP-based approach would offer many advantages including: i) non-invasive magnetic resonance imaging (due to magnetic core) and Raman imaging (due to the gold shell) capabilities, ii) magnetic field-facilitated delivery ('magnetofection') of gene vectors into the stem cells, and iii) magnetic hyperthermia, which will be used to provide a mechanism for the activation of the delivered gene. Overall, the proposed MCNP approach will bring a methodology to the forefront that can allow the user to achieve spatial and temporal control over cellular differentiation, while potentially maintaining the neuroprotective properties innate to stem/precursor cells. In this way, scientists and clinicians can harness the full potential of stem cells (i.e. intrinsic therapeutic properties and controlled cell fate specification) for an enhanced SCI treatment.

PUBLIC HEALTH RELEVANCE: We are developing a magnetic-core shell nanoparticle-based therapeutic platform, which can serve the dual functions of delivering a plasmid encoding an oligodendrocyte-promoting transcription factor (i.e. Olig2) under a heat shock promoter and triggering expression of this vector through magnetic hyperthermia (i.e. using an alternating magnetic field). By delivering this construct to neural stem/progenitor cells, our approach will allow biologists/clinicians to spatiotemporally control the differentiation of these cells to oligodendrocytes, which would facilitate the remyelination of damaged axons incurred due to spinal cord injury.