Objective . Picosecond pulse electric fields (psPEF) have the potential to elicit functional changes in mammalian cells in a non-contact manner. Such electro-manipulation of pluripotent and multipotent cells could be a tool in both neural interface and tissue engineering. Here, we describe the potential of psPEF in directing neural stem cells (NSCs) gene expression, metabolism, and proliferation. As a comparison mesenchymal stem cells (MSCs) were also tested. Approach . A psPEF electrode was anchored on a customized commercially available 3D printer, which allowed us to deliver pulses with high spatial precision and systematically control the electrode position in three-axes. When the electrodes are continuously energized and their position is shifted by the 3D printer, large numbers of cells on a surface can be exposed to a uniform psPEF. With two electric field strengths (20 and 40 kV cm ⁻¹ ), cell responses, including cell viability, proliferation, and gene expression assays, were quantified and analyzed. Main results . Analysis revealed both NSCs and MSCs showed no significant cell death after treatments. Both cell types exhibited an increased metabolic reduction; however, the response rate for MSCs was sensitive to the change of electric field strength, but for NSCs, it appeared independent of electric field strength. The change in proliferation rate was cell-type specific. MSCs underwent no significant change in proliferation whereas NSCs exhibited an electric field dependent response with the higher electric field producing less proliferation. Further, NSCs showed an upregulation of glial fibrillary acidic protein (GFAP) after 24 h to 40 kV cm ⁻¹ , which is characteristic of astrocyte specific differentiation. Significance . Changes in cell metabolism, proliferation, and gene expression after picosecond pulsed electric field exposure are cell type specific.

Huntington9s disease (HD) is a rare autosomal dominant neurodegenerative disorder caused by a cytosine-adenine-guanine (CAG) trinucleotide repeat (TNR) expansion within the HTT gene. The mechanisms underlying HD-associated cellular dysfunction during pluripotency and neurodevelopment, are poorly understood. Here we tested the hypothesis that hypomethylation during cellular reprogramming leads to up-regulation of DNA repair genes and stabilization of TNRs in HD cells. We sought to determine how the HD TNR region is affected by global epigenetic changes through cellular reprogramming and early neurodifferentiation. We find that early-stage HD-affected neural stem cells (NSCs) contain increased levels of global 5-hydroxymethylation (5-hmC) and normalized DNA repair gene expression. We confirm TNR stability is induced during pluripotency, and maintained in HD-NSCs. We also identify up-regulation of 5-hmC catalyzing ten-eleven translocation (TET1/2) proteins, and show their knockdown leads to a corresponding decrease in select DNA repair gene expression. We further confirm decreased expression of TET regulating miR-29 family members in HD-NSCs. Our findings demonstrate that mechanisms involved in pluripotency recover the selected DNA repair gene expression and stabilizes pathogenic TNRs in HD.

The delivery of pulsed electric fields to biological cells for regenerative research and therapeutic applications is a field that has been widely explored. Picosecond pulsed electric fields have been shown to induce intracellular effects and directly target cell membrane proteins as well as being able to induce cell permeabilization and death by apoptosis. Additionally, ultrashort pulses can be focused and delivered in a noncontact manner for possible targeting of deep and inaccessible tissues. The unique characteristics of picosecond pulses make them a possible approach for treatment of Huntington's and Alzheimer's diseases, both characterized by progressive neuronal degeneration and death, and presence of intracellular and extracellular protein aggregates. In this study, the defining characteristics of picosecond pulses and neurodegenerative diseases are reviewed, and a description of how picosecond pulsed electric fields can be applied to disrupt protein aggregates, can target neural stem cell differentiation, and can be delivered to neurological tissue is provided.