Modulation of Electrophysiology and Plaque Aggregation in Huntington’s Disease Patient-Derived Cells by Picosecond Pulsed Electric Fields

Abstract

Huntington’s Disease (HD) is a fatal, autosomal dominant neurodegenerative disorder characterized by progressive motor and cognitive decline. Unstable expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the huntingtin gene, often exceeding 35–40 repeats, results in an extended polyglutamine (PolyQ) tract in the translated protein. Abnormal folding of the mutant huntingtin (mHTT) protein leads to accumulation and aggregation within the cell, dysregulating various cellular processes through molecular sequestration. While several therapeutic strategies have been proposed, this disease remains incurable with treatments limited to symptom management. Pulsed electric fields (PEF), primarily in the microsecond and nanosecond ranges, have been studied extensively for the manipulation of biological systems. With advances in technology, picosecond pulsed electric fields (psPEF) have recently become an area of interest due to their predicted ability to access intracellular and molecular-scale targets while reducing reliance on classical plasma membrane electroporation under selected exposure conditions. Based on computational and experimental modeling, we hypothesize psPEF can fragment amyloid plaques and modulate cellular function in Huntington’s Disease patient-derived cell lines. Using a custom 3D bioprinter-based stimulation system, we exposed HD neural stem cells (NSC) and 28-day forebrain neurons to psPEF at 20 kV/cm and 40 kV/cm in a controlled and reproducible manner. In NSC, quantification of PolyQ punta revealed reduced aggregate burden and subcellular redistribution. Mitochondrial membrane polarization and gene expression alterations were also observed. For neurons, psPEF stimulation temporally and positively altered electrophysiological activity. This was coupled with an upregulation in brain derived neurotrophic factor (BDNF) and dopamine D2 Receptor (DRD2), suggesting improvements to neuronal connectivity and maturation. Differing from NSC, neurons exposed to psPEF under the same conditions did not exhibit a reduction in PolyQ punctations following pulse exposure. However, the visual presence of PolyQ alone does not distinguish abundant colocalization from true aggregation. Differences in cell morphology and electrochemical properties between the two cell types would likely necessitate additional psPEF treatments or varied pulse parameters to achieve the same degree of disaggregation in neurons. Taken together, these findings lay the foundation for developing psPEF into a drug-free, non-invasive therapeutic against Huntington’s Disease and other proteopathic, neurodegenerative disorders.